OMG

I have fallen in love with French cinema myself over the past decade. I have found that you really can't go wrong by the releases primarily from The Criterion Collection--they provide a very good introduction to classic directors and styles from any country. Check out releases by directors such as Truffaut, Godard, Varda, Demy, Tati, Chabrol, Clouzot, etc., and find out what works for you.

These films by the same director are somewhat similar in mood : Le Quai des Brumes and Hôtel du Nord. Excellent films too.