It seems quiet in the morning, but only if you don't know the score. Sunday morning is for church and/or the market or a last minute trip to the local shop and, for sure a trip to the bakery for bread and, perhaps, a fancy dessert. Its also a time in the summer when brocantes (flea markets) and vide greniers (garage sales) are held. The Sunday markets are particularly important as they're where you catch up on all the latest gossip.
Thus the local shops, bakeries and markets are open, but not much else. The local gas station will be open if there's a market, but not if not. We do have one of the large supermarkets over in Villefranche opening on Sunday morning, but they're the only one. This Sunday morning opening by the way is a main reason why most of these same shops are closed on Monday. Everybody needs a full day off.
Sunday afternoons are for eating and spending time with family and/or friends. Mostly this is done at home, but in our area almost every restaurant puts on a special Sunday lunch. Many of the local families go out to eat on Sunday about once a month. Its a treat for everybody & gives 'the cook' a Sunday off. If you want Sunday lunch at one of the better places then you'd better make a reservation otherwise you'll be lucky to get in. On the other hand you'd better eat lunch or have food to hand Sunday evening as you certainly won't find an open restaurant anywhere around here.
I'm afraid that the above is part of "old" France; the way it used to be all over. These days I think that the French who live in cities & larger towns are going the way of the states. Sunday is just another day with most things open. A pity, I think.
If Sunday lunch is at home as it most often is then its a long drawn out affair. Many small courses served with plenty of time between each one. The Sunday lunch I described a couple of posts ago took over 4 hours and was pretty typical. Contrary to popular opinion not a lot will be drunk at these lunches. Most French women we know drink very little; an apero & a glass of wine with the meal - that's it. The men drink more, but still not a lot. An eau de vie or digestif to finish is traditional.
Its a nice way to spend Sunday and reminds me of my childhood when we did much the same. Its nice that many of the French are keeping up the tradition as are the Italians and the Germans. The British, unfortunately, seem to be going the way the states have.
C'est la vie I'm afraid.