Cadastre France

The challenge

France provides a large amount of open cadastral, administrative, planning and property data, but it is distributed across many government services and published in different formats.

Some information is available through APIs and geospatial services, while other datasets need to be downloaded, processed and imported into a local database. Much of the documentation is available only in French.

The challenge was not simply to display a map. It was to identify the right official sources, understand how their data relates to each other and turn them into one consistent experience centred around a property or cadastral parcel.

My role

I built the application from scratch based on supplied Figma designs, working across frontend, backend, data processing and production deployment.

My responsibilities included:

• Building the Laravel and Livewire application
• Implementing the interactive map and cadastral layers
• Developing address, municipality and parcel search
• Researching and integrating French government services
• Creating import processes for large public datasets
• Combining cadastral, planning, property and administrative information
• Calculating parcel and building coverage data
• Building lead-generation workflows and PDF property reports
• Preparing and deploying the application to production

Interactive maps and public data

I built the map interface with Leaflet and OpenStreetMap, adding vector tiles and geometry from French cadastral services to display parcel boundaries, buildings and parcel numbers.

Users could search by address, municipality or cadastral identifier and explore information connected with an individual parcel. Using Turf.js, the application calculated intersections between parcel and building geometries to determine built and unbuilt areas.

The platform combined live integrations with data imported into its own MySQL database. Its sources included API Adresse and IGN Géoplateforme for search and geocoding, DVF property transactions, building and demolition permits, and planning information from Géoportail de l’Urbanisme.

I built import processes that normalised larger datasets from several government sources and connected them through administrative and cadastral identifiers. MySQL spatial functions were also used in an offline process to identify and store relationships between neighbouring municipalities.

From property search to business workflow

Cadastre France was more than a standalone map viewer. Property searches brought together cadastral, transaction, planning and administrative information in one place.

I built the workflow for turning this research into leads and passing submitted details to an external lead-management system. I also developed PDF property reports combining selected cadastral and property information with a map view.

This connected the public-data experience with a practical commercial process while keeping the user-facing journey focused on a specific property.

AI-assisted research

This was one of the first projects where ChatGPT became a meaningful part of my development workflow.

The required information was spread across numerous French government websites, datasets and technical services, often documented only in French. I used ChatGPT to identify promising official sources, understand unfamiliar terminology and navigate the available documentation, then verified the findings against the original services before implementing each integration.

This significantly reduced the research time needed to work through an unfamiliar data ecosystem, helping deliver the project faster and at a lower cost.