In a supermarket « rayon vins spiritueux » or « rayon alcool apéritif ».
In a « cave » a small shop specialized. A cave
sells good quality wine, also wine from the region. There you'll have a wider choice and good advice.
You won't find in a French cave these kinds of big fridges you can walk inside to buy a cold beer. Acohol isn't sold refrigerated and most caves do not sell beer except high quality beer.
In a cave you can also buy your wine « en bouteille » or « en vrac ».En vrac means you come with your bottle and buy directly from a big cuve. Often it's a good way to try a good local wine from a small produce "vin de pays".
And if you are brave and interested, go to a vineyard (vignoble, chez un vigneron) and buy directly from the producer. Most of
the time it's less expensive. But be careful, the big and famous wineyards have already earned so much money, they don't really care about people like you and me. In some of them, they won't let
you taste their wine. Try smaller and less famous vineyards, people there might be nicer.
Back to the alcohol list