We've enjoyed sitting in German Biergarten and Viennese wine gardens, but now we're going back to France for about a month next year in May-June. What do they have that is similar - wine, music, lite food, outside, peaceful...? Where can we find it? Our travel is very flexible - we're just now putting our itinerary together and we'll gladly plan around outdoor music and wine. Don't want college kids getting drunk parties, just neighborhood hangouts. We'll be starting in Toulouse and heading to Paris.
There used to be things called "guinguettes" that were similar, often on the banks of rivers, but they're very rare now. Many restaurants, cafes, and bars will have tables outside on the street in summer, and some may have them in open courtyards or gardens (rarely in city centres, due to the expense of land), but live music is very rare.
Well, that is sad. Maybe we'll be lucky and stumble onto some music somewhere.
Try to be in France on the Summer Solstice for the Fête de la Musique (https://www.fetedelamusique.culture.fr/en/International/presentation/). We were in Aix-en-Provence when it happened in 2012. It was fabulous. Just be aware that musicians may be rehearsing a couple of days, or rather, nights, in advance and it can get pretty noisy wherever you stay on the day it happens and the days leading up to it.
You can also take a look at this very website -- https://www.ricksteves.com/europe/france/festivals -- for events that include music and go to the links provided or Google them for more info.
In Paris, on the Ile St. Louis, the Brasserie de L'Isle Saint-Louis has outdoor seating with a bit of a view. The park at the tip of that island is also a good picnic spot. Your picnic at the Champs de Mars, Place de Vosges, etc, can include, wine, beer, or anything that attracts you at the market. Special events often are staged in front of Paris' Hotel de Ville.
Thanks Laura, we'll take a look at all of those suggestions.