We recently published a data study on the French business registry — 14.4 million active establishments, sliced by workforce, sector and geography. The numbers themselves aren't the interesting part for this post. What is: the rules we forced ourselves to follow so that anyone re-running the same queries on the same open dataset would get the exact same numbers, and so every headline percentage could be traced back to a total someone else can check.
This is a walkthrough of that process, using INSEE's SIRENE registry (France's official open-data business registry) as the example dataset, because it's public, it's messy in the ways real government data tends to be, and the mistakes we ran into are the boring, common kind — not exotic edge cases.
Reconcile before you round
The registry snapshot we worked from (dated July 1, 2026) contains 14,387,175 active, publishable establishments and 26,756,173 legal units in total, of which 14,470,762 are active. Those three numbers are the anchor for everything else: before computing a single percentage, we re-derived each of them independently from the raw stock and diffed against the reference totals published alongside the dataset. Zero-diff or the query is wrong — not the data.
