Why precedent shapes the whole case
In merger control, the decisional practice of the French Competition Authority is not case law in the strict sense, but it comes close: the Authority reuses its own market definitions, analytical thresholds and remedy templates from one case to the next. Knowing the relevant precedents means anticipating how it will read your transaction.
An experienced practitioner does not look for a single magic decision, but reconstructs the lineage of decisions that shaped a sector's analysis: how the market was defined, which market-share thresholds triggered concerns, which remedies were accepted or rejected.
Start from the sector, not the decision number
The first mistake is to search by number. A decision number (for example 13-DCC-90) only sticks once you have already encountered it. The right entry point is sectoral and factual: type of activity, store format, geographic dimension of competition.
For a food-retail transaction in Paris, the reference lineage starts with decision 13-DCC-90 (Casino / Monoprix), where the Authority retains short catchment areas — around 300 to 500 metres on foot — and increased substitutability between store formats in dense areas.
- §Identify the relevant product market(s) — upstream, downstream, by format.
- §Specify the geographic dimension: national, regional, local, overseas.
- §List comparable transactions already reviewed in that sector.
The relevant market as a search key
Market definition is the most discriminating entry point. Two transactions in 'retail' may belong to entirely different markets depending on whether they involve food-led distribution, specialised retail or online sales.
An effective search therefore combines demand-side substitutability (does the consumer treat the banners as interchangeable?) with the Authority's prior practice on that perimeter. This matching work is exactly what L420 automates: you describe the deal, the engine retrieves the decisions where the Authority ruled on analogous market questions.
Work backwards from accepted remedies
When the stake is residual competitive risk, the best search angle is often the remedies. Searching for 'which commitments were accepted' in a given sector surfaces the most instructive decisions about the parties' real room for manoeuvre.
For example, in overseas markets, decision 20-DCC-72 (GBH / Vindémia) shows that store divestitures were required from a 50% market share, with an up-front approved buyer — a strong signal of the Authority's level of scrutiny in those areas.
Always verify the source
A precedent is only worth citing if you can pin it down precisely. The reference (decision number, paragraph) must be verifiable: that is what separates a solid working note from an unverifiable claim.
This is L420's reason to exist: every answer is grounded in the excerpts actually retrieved from the Authority's corpus, with references attached. When the corpus says nothing relevant, the tool flags it rather than extrapolating.