The South of France isn't specialised in beer, I'm afraid. The favourite drinks around there are pastis (my preference going to the HB brand) and rosé wine.
I was there last year (Nice and Marseille), and didn't bump into any craft brew.
My advice would be
1) Stay away from so-called Irish pubs, especially in Marseille. There's a nice one in Martigues, in case you're passing by, but not worth the diversion.
2) Like in any bar in France, you can ask for a "Monaco". Make sure you know that you'll be served a shandy with grenadine syrup.
3) In French we use the same word "brasserie" for a brewery and for a popular restaurant, beware.
