They find places like this lined with lavender to have lunch in the sun.
They don’t mind if the table is on the sidewalk as long as they are in the sun. I always have to sit in the shade myself.
In some parks you can’t sit on the grass so people sit on benches and chairs if they are available. When there is no sign banning getting on the grass, it is packed with people.
They eat ice cream although I imagine most of the ice cream is eaten by tourists, not French women watching their weight
Or you lie in the sun on Paris Plage, a false beach along the Seine, put there each August.