Please allow me to recommend the Cave à bières à Rennes : Chez Alain .
The French are more into drinking wine, but this shop does beer a lot of justice.
They have around 350 varieties of beer, both imported and domestic.
It also has a small bar situated on site. What more do you need?
Beer cellar in Rennes : Chez Alain
A wide range of artisanal beers from all over the world in Ille-et-Vilaine
Discover a variety of 100% artisanal beers made from carefully selected malt. Beers from Brittany, Belgium, Europe, or the rest of the world, select your favorite beer.
Push the doors of our beer cellar in Rennes and discover our novelties and our latest arrivals. You will find 350 references of French and foreign beers (Belgium, United States, Canada, Scotland, Norway, Sweden, Italy, Denmark, Holland, England, Switzerland, Germany, Czech Republic…).
Having been there some years ago, it is awesome.
Caveat:
On-line shops may only do sales on-line and may or may not have an inventory shop to browse in. Some are simply middle men so to speak.