Digital sovereignty: SecNumCloud vs APPI, how we navigate.

You're CIO of a group with operations in France, Japan, and North America. On the Paris side, your DPO demands SecNumCloud and data hosted in Roubaix. On the Tokyo side, your legal talks about the revised APPI and the Economic Security Promotion Act, but accepts AWS Tokyo. On the Montreal side, they talk about Law 25. Welcome to the multi-jurisdiction sovereignty puzzle.

France: SecNumCloud as dogma

Since the SREN law and the "Cloud at the center" circular, SecNumCloud is near-mandatory for anything touching sensitive public or health data. ANSSI doesn't joke around: US hyperscalers, even via partnerships (Bleu, S3NS), are not qualified today. You arbitrate between OVH SecNumCloud, Outscale, Scaleway. Narrow, but clear.

Japan: apparent pragmatism, hidden requirements

Japan has no strict SecNumCloud equivalent. AWS Tokyo, Azure Japan East, GCP Tokyo are widely used, including by banks. But the Economic Security Promotion Act (2022) classifies certain sectors as "critical infrastructure": finance, energy, telecoms, transport. For those, localization and audit requirements apply, fuzzier but very real. The 2022 APPI adds constraints on international transfers of personal data, similar to GDPR but not identical.

The hybrid architecture that passes both audits

For a Franco-Japanese industrial client (3,000 people, operations in both countries) we built an architecture that simultaneously satisfies ANSSI and METI. The principles:

• Strict data separation by jurisdiction. French data stays in France (Outscale Cloud Gouv), Japanese data stays in Japan (AWS Tokyo + local KMS encryption).
• Unified control plane, federated data plane. A single admin console (hosted in a European sovereign cloud), zero operational data flow cross-region.
• E2E encryption with client-held keys. AWS KMS Custom Key Store on the Japan side, Atos Trustway on the France side. No cloud provider can read in clear.
• Centralized audit trail via OpenTelemetry, anonymized and exported into a SIEM hosted in Switzerland for jurisdictional neutrality.

Compliance as code

hcl
# OpenTofu : provisioning multi-region avec contraintes souveraines
module "data_plane_fr" {
  source   = "./modules/sovereign-fr"
  provider = outscale.eu_west_2
  
  data_classification = "RESTRICTED_FR"
  encryption_kms      = var.atos_trustway_key_arn
  audit_export        = "siem-eu-only"
}

module "data_plane_jp" {
  source   = "./modules/sovereign-jp"
  provider = aws.ap_northeast_1
  
  data_classification = "APPI_PERSONAL"
  encryption_kms      = var.aws_kms_jp_cks_arn
  cross_border_transfer = false  # Hard constraint
}

GDPR + Japan Supply Chain Security: what you need to know

Since 2024, Japan has strengthened its requirements on the software supply chain (Supply Chain Security Guidelines, METI). Concretely, you must document every open-source dependency, every subcontractor, every third-party service. This aligns with the SBOM (Software Bill of Materials) imposed by the European Cyber Resilience Act. Good news: doing both at once costs 1.2x, not 2x.

The trade-offs nobody wants to make

Wanting strict SecNumCloud AND AWS Bedrock for LLMs AND global CDN performance: it's incompatible. The CIOs who succeed are those who accept to classify their data by real criticality, not generic paranoia. 80% of a company's data doesn't need SecNumCloud. The remaining 20% does, and those 20% deserve a dedicated architecture.

If you operate across multiple jurisdictions and your compliance matrix fits in three unsynchronized Excel files, our Franco-Japanese teams have already designed and certified this type of architecture. Let's talk before the next audit.