How acceptable is athleisure in Paris, and France generally?

Thinking about what to pack. I would prefer to take mostly athleisure type clothes for comfort and warmth. Newer and nicer stuff, not my most ancient sweatpants and trainers.

I will mostly be exploring the city (architecture nerd), seeing a few museums, eating at casual local places. So nothing fancy and I won't need to really dress up.

Buuuuut, how accepted is this style of clothing in Paris? or elsewhere in France?