Train from Chamonix to Paris?

Once again, Rome2Rio strikes out swinging.

Train: Chamonix Mont Blanc to St Gervais les Bains, change to train to Bellegarde, change to TGV to Paris Gare de Lyon.

Another option is to take the bus to Geneva and then the train to Paris. The train
out of Chamonix is a tad inefficient and has 1 or 2 connections. If you hit it right,
the bus + train may be faster.

Buses from Chamonix to Geneva mostly go to the airport, where you will then have to take a train to Cornavin Station where the Paris TGV departs from. The other option is Flixbus to Place Dorciere Bus station, which is about a 1/4 mile walk from Cornavin Station.

The TGV from Geneva to Paris stops at Bellegarde, where it meets the train from St Gervais les Bains (and by connection, Chamonix).

Thanks for the information everyone! As we will be traveling on a Sunday , there are fewer trains but definitely enough to meet our needs. Next question….. is Flixbus or Blablabus better to take from Chamonix to Annecy or Geneva?

Flixbus from Chamonix to Annecy is direct and a lot quicker, like 1 1/2 hours. To Geneva is also direct to Place Dorciere in Geneva. Some are 1 1/2 hours and some are 2 1/4 hours. The 2 1/4 hour trips are to the airport first, then to Place Dorciere.

I know nothing about blablabus.

Flixbus is just fine, especially for a short ride like this. There is also a public bus
(was #272, not sure about now) which makes a lot more stops but is cheaper.

I have not used BlaBlaBus, but am under the impression it's a motor coach service
similar to Flixbus.

At the end of the day, bus vs train from Chamonix to Geneva is a bit of a wash, IMO.
The bus itself is faster but the connection can be a bit more involved. The train is
slower but the connection(s) is a bit easier.