Please note that tomorrow's protest route in Paris will be:
Depart from Place de la République at 11h
go via blvd Voltaire
Arrive at Place de la Nation at 19h
this is likely to be a well-subscribed march, so it may NOT be the day to visit République, Bastille, Père Lachaise, etc.
Surface transportation such as buses will definitely be affected -- lines cancelled or shortened -- and taxis as well.
Often the police authorities also close down metro stops right near the marches, so check CityMapper and/or https://www.ratp.fr/infos-trafic and/or the Twitter feed of the metro line you plan on taking if you're somewhere near the protest route to see if your metro stop will be affected.
This is far from the Louvre, the Orsay, the Eiffel Tower, the Arc de Triomphe etc, so shouldn't create a problem for most visitors unless you had a lunch reservation somewhere along the blvd Voltaire!
Edited to note: Some press is reporting that estimates of participation in the Paris march tomorrow range from 90,000 to 120,000 people.