I think the only tours that are running in France right now are the Best of Paris. There are ones scheduled to start on the 15th, 22nd and 29th so there should be one going in Paris now. The ones in Paris normally take the Metro everywhere altho we did have a bus for a couple of hours for a city sights tour when I did this tour.
Knowing the strike was coming I'd be very surprised if the guides and the office hadn't worked out alternatives for tour days. One of the days is Versailles so it would be possible to hire a bus for that trip.
This tour often stays at the Hotel Londres Eiffel. It is about a 10 minute walk from there to the Alma-Marceau Metro stop which looks like it has some trains running. That can connect to Line 1 which is automated and running. I did see pictures posted on FB earlier today of packed hallways at Chatelet tube station so that would be a concern
It's not too bad a walk to d'Orsay and Orangerie from this area and I would typically walk from the Notre Dame area back to this neighborhood but it might be a lot for a tour group.