While it's likely that such high-quality cheesemongers are strewn throughout France, this is and…read morehas always been my favorite - since childhood.
Nestled just off of Place Guillaume le Conquerant (what, you thought it'd be William the Conqueror Plaza?) is this gem of a Fromagerie. Good luck NOT finding whichever of the hundreds of French cheeses sourced from around the country. La Fromagerie may even purvey cheeses from outside the Hexagon, but I can't imagine how well those could sell.
My pictures may give you some insight on what you can expect. I bought four cheeses (depicted in the window-sill shot) and they made for a fantastic cheese-tray offering for the week. An Epoisses, a phenomenal Neufchatel (In the U.S., "Neufchatel" is the name that was hijacked to indicate a light cream cheese, and has nothing to do with this creation here), a sublime Bleu d'Auvergne, and a 4-year old Comte.