Opinion piece published in Smart City Mag on May 16, 2025.
By Pascal Zératès, CEO of Kardham Digital.
The concept of the smart building is now becoming a given in real estate strategies, energy policies, and office development projects. To address this, an Anglo-Saxon term has recently emerged in the French landscape: Master System Integrator (MSI).
This term, referring to a player capable of ensuring the technical integration of a building’s digital systems, has quickly gained traction in literature and even in tenders. However, behind this appealing façade lie significant limitations. As challenges expand—user journey personalization, cybersecurity, operational continuity, digital sovereignty—the simple role of an integrator is no longer sufficient. It is time to move into a new phase in the development of smart buildings, one where digital intelligence does not merely assemble systems, but designs, adapts, operates, and evolves them. The stakes are high. The global market, growing at 11% annually, is expected to reach $121.6 billion by 2026*.
MSI, an already outdated model
In recent years, the concept of the Master System Integrator (MSI) has established itself as a reference framework in smart building projects. Presented as the central actor in integrating software and hardware layers within intelligent buildings, the MSI theoretically acts as the conductor of heterogeneous solutions. In practice, however, this model quickly shows its limits. First, because the MSI does not control what it integrates. It remains dependent on third-party vendors for the software solutions it assembles. This dependency creates both technical and organizational tensions: difficulty keeping pace with updates, incompatibilities between modules, and a lack of agility when adapting to specific uses. The result is often a building overloaded with stacked layers—a technological “layer cake”—which undermines the overall coherence and performance of the system.
The trap of the technological layer cake
This accumulation of technical layers also results in low adoption of digital management tools in buildings: only 6% of tertiary buildings over 1,000 sqm are currently equipped with digital systems enabling efficient energy management. This figure is particularly alarming given the national target of reducing energy consumption by 60% by 2050**.
This “layer cake” is not just an architectural issue—it is also an economic dead end. Each level of integration brings its own margin, dependency, and complexity. By relying on external proprietary solutions, the MSI adds costs without necessarily creating long-term value. This “software burger” logic—where each ingredient comes with its own constraints and margins—runs counter to the efficiency expected from intelligent building management.
But it is from a user perspective that the limitations become most evident. In smart buildings, every project is unique. Expectations regarding user experience, comfort, maintenance, security, and energy management vary significantly from one building to another. Yet an MSI assembling standardized components cannot fully address this diversity. Adapting interfaces, tailoring services, and customizing information flows becomes a challenge—sometimes an impossible one—within a rigid integration framework.
Another often underestimated constraint is that software platform providers, no matter how efficient, cannot meet all the specific needs of each project. Designed for broad markets, their solutions tend to standardize functionalities, limiting their ability to finely adapt to specific use cases, business requirements, or local contexts. This mismatch further reinforces the limits of an assembly-based integration model.
The ESN, a key player in smart buildings
This is where another figure emerges: the Digital Services Company (ESN – Entreprise de Services Numériques). More flexible and cross-functional, the ESN is capable of designing, developing, integrating, and evolving tailor-made solutions. It goes beyond system assembly, acting as a true digital prime contractor at the intersection of IT, OT, and IoT challenges. The ESN has a dual critical capability :
- producing software components tailored to specific use cases
- integrating them into complex ecosystems, often already partially in place
This integrated approach ensures continuity from initial design to system construction (“build”), deployment, and long-term operation (“run”). In an environment where uses, standards, and technologies constantly evolve, this end-to-end control becomes a decisive advantage.
Towards sovereign and scalable digital intelligence
Limiting smart building thinking to the MSI function underestimates its complexity. A smart building is not just a technical platform—it is a living, connected environment where data, flows, and uses converge. It requires digital intelligence that is not only integrated, but coherent, manageable, scalable—and sovereign. Its development also requires the ability to create solutions locally, ensuring cybersecurity for buildings, users, and data, while preserving digital sovereignty—especially in sensitive environments.
The future of smart buildings does not lie in a siloed separation between software vendors and integrators, but in organizations capable of delivering projects end-to-end, with a combined technical, operational, and strategic vision. In this context, the ESN for buildings—combining MSI capabilities with software publishing as a “Global Services Provider”—can emerge as the natural backbone of smart buildings. By moving beyond the limitations of the MSI model, it restores the full meaning of the word “smart”: not just a “connected” building, but a truly intelligent one—designed, operated, and transformed within a sustainable, sovereign, and contextualized service logic.
Sources
*MarketsandMarkets, Smart Building Market – Global Forecast to 2026.
**Xerfi, Étude sur le marché du smart building en France.