I like July, an especially interesting month in Paris because people slowly start to seep out of the city. Paris is filled with the sounds of luggage rolling over the rough streets, as people make their way to train stations and to the airport, to get out of town for their annual vacances (vacations), returning in late August or early September, for the rentrée.
The city can be blissfully quiet (although sometimes, blazing hot) in the summer and many, including myself, say it's our favorite time in Paris. The sidewalks are sparsely populated and a majority of the places - restaurants, cafés, and bakeries – close up, so the staff can split, too. The eateries and bakeries that are open are calm and relaxed, everyone soaking in the respite for the normally hectic pace of city life.
During the past few years, though, more and more places have stayed open, which is nice for visitors. (And those of us who stick around...) Many Americans, and others, also vacation in August and are concerned about places being shuttered. My advice is if you're coming in the summer, don't arrive with a fixed list of places you want to go, but wander around and find little cafés and restaurants that don't have famous names, but are convivial neighborhood spots where locals hang out. There's nothing I like better than to sit in a café, or by the Seine, with a carafe of rosé, chatting with friends, while watching the world saunter by. And refilling our wine glasses...again and again.