Under CRA Blue Guide concepts, which first supply transaction matters for placing on the market?
The first one.
For the individual product, the legal placing-on-the-market event is the first supply for distribution, consumption or use on the Union market, whether that first supply is to an importer, a distributor or directly to the end user.
Supports the answer on the first supply to an importer, distributor or end user being the relevant placement event; section 2.3.