The choice between building or buying a sovereign cloud solution in 2026 boils down to control, cost, and compliance. French organizations must decide whether to create their own infrastructure for full autonomy or purchase pre-built solutions for faster implementation. This decision is influenced by strict European regulations like GDPR and SecNumCloud certification, which prioritize data sovereignty and limit non-EU ownership.

Key Takeaways:

• Building: Offers full control over systems and compliance but requires high upfront costs, technical expertise, and ongoing management.
• Buying: Provides faster deployment and access to provider-managed services but comes with higher operational costs and limited autonomy.

Quick Overview:

• Build: High initial investment, full legal control, avoids vendor lock-in, slower to implement.
• Buy: Predictable costs, quicker setup, but risks jurisdictional ties and vendor dependency.

The choice depends on your organization's needs for control, compliance, and scalability. Up next, we’ll explore the pros and cons of each approach and practical strategies to navigate these challenges.

Architecture for the Sovereign Cloud

sbb-itb-e314c3b

1. Building Your Own Sovereign Cloud

Creating your own sovereign cloud gives you complete control over everything - data centres, encryption keys, and beyond. However, this route demands a hefty upfront investment for hardware, connectivity, and facilities, along with ongoing costs for maintenance, security, and updates. To illustrate the scale, Amazon has invested nearly €8 billion in a sovereign system tailored to meet stringent EU requirements. This approach ensures compliance with ANSSI's SecNumCloud standards and shields you from the reach of extraterritorial laws.

The technical demands are no small feat. Your organisation will need EU-based experts with skills in encryption, OpenStack, Kubernetes, and infrastructure optimised for AI. HPE's data shows the growing interest in this model, with sovereign and enterprise bookings accounting for over 60% of cumulative orders between Q1 2023 and late 2025. Yet, governance remains a challenge - an April 2025 survey revealed that only 35% of IT leaders have full visibility into where their data is stored and managed. This highlights the complexity of handling data sovereignty in-house.

"User priorities are shifting towards personalisation and the private domain. This is accompanied by growing emphasis on efficiency, response speed, security, privacy and sustainability." - Yuanqing Yang, Chairman, Lenovo

Given the technical hurdles, managing costs becomes essential. High-level technical requirements lead to substantial capital and operational expenses. A smart strategy is to start with sectors like healthcare and defence, where sovereignty is a must, and then expand gradually. To keep long-term costs in check, prioritise energy efficiency with low Power Usage Effectiveness (PUE) and renewable energy sources. The EU's Sovereignty Effectiveness Assurance Level (SEAL) framework can guide your efforts - achieving SEAL-4 (Full Digital Sovereignty) requires complete EU control with no critical non-EU dependencies, significantly increasing resource needs compared to lower levels.

One clear advantage of building your own system is flexibility. You can design modular, interoperable architectures using open standards, which helps avoid vendor lock-in and allows for seamless workload migration without major re-architecture. Local encryption key management is another must-have, ensuring your organisation maintains cryptographic control rather than relying on an external provider. This autonomy is critical for meeting the EU Cloud Sovereignty Framework's eight Sovereignty Objectives (SOV-1 to SOV-8), introduced in October 2025.

To navigate these challenges, the Build-Operate-Transfer (BOT) model offers a practical middle ground. This approach involves partnering with hyperscalers or local firms to build your infrastructure initially, then transitioning to full internal control as your team gains expertise. To ensure your system delivers the autonomy and resilience you’ve worked for, conduct annual "sovereignty drills." These simulations test your readiness for scenarios like provider outages or foreign subpoenas.

2. Purchasing a Sovereign Cloud Solution

For organizations looking to speed up compliance and deployment, purchasing a pre-built sovereign cloud solution can be an appealing choice. While this approach offers a quicker route compared to building a custom infrastructure, it’s crucial to weigh the costs, regulatory assurances, and technical trade-offs. Sovereign cloud services generally cost 10% to 30% more than standard public cloud options. This premium stems from factors like isolated infrastructure, strict compliance demands, and screened personnel. For instance, Google’s Sovereign Cloud comes with a 10% to 20% markup, while Oracle’s EU Sovereign Cloud commands a 15% to 30% higher price. However, many providers offset these premiums with perks like subsidized bandwidth or free usage credits for anchor tenants.

When buying a solution, compliance guarantees vary significantly between vendors. In France, the SecNumCloud 3.2 qualification, overseen by ANSSI, is regarded as the benchmark for compliance. Notably, in December 2025, S3NS - a partnership between Thales and Google Cloud - achieved this certification for its PREMI3NS solution. This platform operates out of three data centers in France, staffed exclusively by S3NS employees. Early adopters of PREMI3NS include EDF, Thales, and insurers like MGEN and Matmut. Similarly, Bleu, a collaboration between Orange, Capgemini, and Microsoft, reached SecNumCloud Milestone 1 in November 2025. Orange Business has even pledged to migrate 70% of its IT systems to Bleu’s platform. These joint ventures are structured to ensure protection from extraterritorial laws like the US CLOUD Act, as they are considered French entities operating under French law.

"The US government cannot serve a CLOUD Act warrant on S3NS or Bleu because neither company is a US person or subject to US jurisdiction." - Julien Simon, AI Sovereignty Expert

Still, technical limitations remain a challenge. For example, AWS launched its European Sovereign Cloud in January 2026 with around 90 services - far fewer than the 200+ services available in their standard regions. This service gap is largely due to the rigorous security checks and quarantine processes required for compliance. At S3NS, updates from US-based technology partners undergo thorough analysis in a quarantine environment before deployment. To balance these constraints and costs, many organizations are turning to hybrid sovereign landing zones. This approach combines cost-effective global public cloud resources for non-sensitive tasks with sovereign cloud environments for regulated data . Automated data classification tags (e.g., public, restricted, or secret) help ensure only sensitive information is routed through the higher-cost sovereign infrastructure.

Before making a decision, it’s essential to evaluate whether the provider’s Service Level Agreements (SLAs) are on par with their standard public cloud offerings. Additionally, consider whether the reduced service catalogue will meet your operational requirements. To manage expenses, shifting predictable workloads to multiyear contracts can save up to 65%, while optimizing compute instances can address up to 30% of budget waste. These strategies highlight the trade-offs involved in adopting a sovereign cloud solution. With sovereign cloud spending expected to grow at an annual rate of 36% through 2028, reaching €160.1 billion, thorough provider evaluation is more important than ever.

Advantages and Disadvantages

Deciding whether to build or buy a sovereign cloud solution involves weighing costs, control, and complexity. Building a solution demands a significant upfront investment, but it can deliver better long-term returns by avoiding vendor lock-in and keeping economic value within local jurisdictions. On the other hand, buying a solution relies on a subscription model with predictable costs, though compliance expenses might increase as providers adjust to evolving EU regulations.

Here’s a quick comparison of the two approaches:

From a regulatory perspective, these differences have a direct impact on compliance and risk. Building a solution provides protection from extraterritorial laws and enables full digital sovereignty under the SEAL-4 framework. In contrast, buying a solution may expose organisations to "sovereignty-washing", where providers offer services that appear compliant but lack true operational or legal independence. Maurice Schubert, Partner at Deloitte, highlights the importance of this issue:

"Digital sovereignty is no longer a buzzword, it is a tangible risk that demands attention at the board level".

Operationally, the two approaches diverge sharply. A custom-built solution requires ongoing management of security updates, governance structures, and internal expertise. Meanwhile, off-the-shelf solutions offer managed services and automation but often at the expense of transparency and administrative oversight.

The choice between building and buying a sovereign cloud solution has far-reaching implications for both technical and operational strategies. Align your decision with the sensitivity of your workloads and regulatory requirements. Planning for sovereignty from the outset is far more cost-effective than retrofitting compliance into existing systems. Additionally, ensure your architecture supports data portability to meet the EU Data Act's requirements and limits management access to authorised personnel certified within the country.

Conclusion

The balance between control and compliance is at the heart of the digital sovereignty debate. French organisations are navigating a challenging landscape, especially with the mandatory adoption of SecNumCloud v3.2, which limits their options. Choosing to build your own infrastructure offers complete control and protection from extraterritorial laws, but it comes with significant upfront costs and demands skilled management. On the other hand, buying through partnerships like S3NS or Bleu combines hyperscaler technology with French legal oversight, providing a middle ground.

To craft an effective strategy, classify your workloads based on their sovereignty requirements. For instance:

• Mission-critical, regulated data: Requires SEAL-4 compliance.
• Intellectual property: Needs strong control measures.
• Commodity applications: Can often rely on standard public cloud solutions.

When evaluating providers, use the European Commission's eight sovereignty objectives as a guide: Strategic, Legal, Data/AI, Operational, Supply Chain, Technology, Security, and Environmental. These criteria help assess transparency and determine SEAL scores.

If you opt to build, consider open-source platforms like OpenStack and Kubernetes to avoid vendor lock-in. For those buying, ensure the provider’s structure avoids exposure to US legal jurisdiction, and regularly conduct sovereignty drills to maintain compliance.

"Digital sovereignty cannot be declared – it must be demonstrated." – Whaller

The shift toward measurable sovereignty is underscored by the European Commission’s €180 million tender launched in October 2025. Regardless of the path you choose, focus on architectures that enable data portability and restrict management access to EU-based personnel. Planning for sovereignty from the outset helps avoid costly adjustments later.

FAQs

What should organizations consider when choosing between building or buying a sovereign cloud solution in 2026?

When deciding whether to build or buy a sovereign cloud solution in 2026, organizations need to weigh several key factors. One of the most pressing is regulatory and compliance requirements. Laws like GDPR and local sovereignty rules demand strict adherence to data residency and security standards. Building a custom solution gives organizations more control, allowing them to tailor compliance measures to their specific needs. On the other hand, purchasing a pre-built solution offers the advantage of faster deployment and access to established, tested technologies.

Another critical factor is technological complexity and operational control. Developing a sovereign cloud in-house requires significant expertise, resources, and a long-term commitment. However, it offers unmatched flexibility and avoids the risk of being locked into a single vendor. Pre-built solutions, by contrast, simplify the implementation process and often integrate seamlessly with existing infrastructure designed to meet sovereignty requirements. That said, organizations need to carefully assess whether the provider’s offering meets their local compliance needs.

Ultimately, the decision comes down to balancing control, compliance, and resource availability. Companies with specific requirements and the technical know-how may lean towards building their own solution. Meanwhile, those looking to prioritize quick deployment and scalability might find that purchasing a pre-built option better aligns with their sovereignty objectives.

How do EU regulations like GDPR and SecNumCloud shape the choice between building or buying a sovereign cloud?

When deciding whether to build or buy a sovereign cloud in 2026, EU regulations like GDPR and SecNumCloud are key factors to consider. The General Data Protection Regulation (GDPR) imposes strict rules on data protection and sovereignty, requiring organisations to adopt solutions that comply with EU privacy standards. Meanwhile, France’s SecNumCloud certification mandates data localisation within the EU, EU-based support services, and limits on ownership by non-EU entities. These requirements make compliance a crucial aspect of any decision regarding cloud infrastructure.

These regulations push businesses toward two main paths: developing their own compliant infrastructure or partnering with certified providers that meet the required standards. Opting for SecNumCloud-certified solutions, for instance, helps organisations protect sensitive data, reduce risks tied to extraterritorial laws, and stay aligned with EU legal frameworks. Beyond being a legal obligation, adhering to these regulations offers a strategic edge in managing the complexities of today's cloud landscape.

How can organisations in 2026 effectively manage costs when building their own sovereign cloud infrastructure?

To keep costs under control while building a sovereign cloud infrastructure, organisations can take a modular and scalable approach. This method allows for step-by-step deployment, avoiding hefty upfront costs and matching expenses to actual operational demands.

Using open-source technologies is another smart move. It not only cuts down on licensing fees but also offers more flexibility in adapting the infrastructure to specific needs.

Prioritising local or regional cloud infrastructure can also be financially wise. Such options might qualify for subsidies or benefit from policies that support European providers, reducing reliance on pricier foreign solutions. At the same time, conducting thorough interoperability and reversibility tests is crucial to prevent vendor lock-in. This ensures the system remains adaptable and scalable without incurring unnecessary costs down the line.

By combining these strategies, organisations can strike a balance between cost management, sovereignty, and long-term resilience.

Related Blog Posts

• The End of the Pilot Purgatory: Scaling AI from Experiment to Enterprise Standard.
• The Chief AI Officer Playbook: 5 Priorities for the Next 12 Months.
• The 2026 AI Investment Thesis: Where Top VCs are Deploying Capital Now.
• From Seed to Scale: Lessons from Europe’s Newest Unicorns.