Agneau is popular but expensive in France, and the French tend to like it rosé (pink); if you want it well done, you need to tell the server (see ordering meat in a restaurant).
If a lamb is over 12 months old, it’s mouton.
Some of France’s finest lamb is agneau pré-salé raised on the salt meadows along the Atlantic coast for at least 75 days after weaning. The sea air and salt that flavour the grasses lends the meat a unique taste without even the slightest trace of salt.
The marshes in Normandy are famous for their AOP Prés-Salés du Mont-Saint-Michel as is the salt meadow lamb from the Somme Bay in the Hauts-de-France (AOP Agneau de Près-salés de la Baie de Somme).
Images by b3rny, Ferme Parquette, Iain Cameron, Nikchick