Apparently the rules for what ingredients you’re allowed in bread are more precisely determined in French law than European law. As a result, a bakery in Barnsley is managing to sell baguettes to that very French institution – SNCF. I’ve tried to look into this is more depth, and via Wikipedia have come across this French bread law, that does indeed seem to prevent adding fat to bread, the ingredient that the Barnsley firm wishes to add to the baguettes to increase their shelf life. As plenty of European Court of Justice case law has shown, EU states cannot prevent the import of goods due to a different definition in another Member State – mutual recognition – and there’s no EU prevention of fat in bread.
So while I wonder about the merits of putting fat in baguettes, there’s nothing the French can do about the baguettes from Barnsley other than to amend their own law, change the EC law definition of bread and its ingredients, or for a French bakery to setup a factory in another EU Member State and sell to SNCF from there. It’s a good case of why EU rules (and elimination of non-tariff barriers) matter to business.