On the last day of the vacation - we saw people running half marathon on a sunny sunny day.
We stayed at Le Marais for 4 days and it was a lovely location although you may not find something spacious if you are looking for cheap accommodation in the heart of the city. It's manageable - the place tightly accommodated 3 of us - Airbnb again
17. Around Marais… Other cool area might be to go to the oldest part of town, called the Marais, and see the Hotel de Ville (city hall), Place Des Voges, and the Picasso museum. Also Centre Pompidu. There are lots of cute restaurants/bars near Centre Pompidu, but it can also be a bit dogy in areas. The Opera and Madeline are cool too, but then again, everything is pretty amazing in Paris.