Chanel has some FABULOUS perfumes that are pretty difficult to find, but you'd absolutely find them in Paris. (And it's a relatively affordable excuse to go in one of their amazing boutiques!)
Chanel no. 22 - the parfum version (the best!) is very rare - easily obtained in Paris.
Bois Des Iles
Cuir de Russie
The latter 3 perfumes are all part of Chanel's "Rue Cambon" collection. They were created in the 1920s by famous Chanel perfumer Ernest Beaux, then discontinued and lost for decades. They were recently brought back, true to their original formulations, but can be difficult to find. Your average Chanel counter in the mall absolutely won't have them. I've tried them all, and found them all DIVINE, but to each their own.
The parfum versions are by far the best, and though they are expensive, a tiny bottle will last forever because you need so little each time you wear it.
(I'm a bit of a fragrance-hound, can you tell? LOL)