Are the metro stations in Paris wheelchair accessible? Are there lifts/elevators? My son is disabled, we are using a stroller in lieu of his wheelchair and I am wondering if it will be difficult to access the metro.
Only Metro line 14 that travels from Northwest to Southeast throughout Paris is fully wheelchair accessible. There are also many RER stations (express underground train line) that are wheelchair accessible with elevator access to platforms and train conductors that can help your son board through use of a wheelchair ramp (only necessary when there's a significant gap, not always present).
Please see the article on wheelchair accessible Paris Metro RER stops and stations for more information on what to expect when using the Paris Metro/RER with a wheelchair.
As for the Metro lines other than Line 14, I wouldn't advise attempting wheelchair access due to the amount of stairs throughout the winding tunnels leading to the train platforms and at times the significant gap between train and platform at some stations.
Buses and trams are another possibility for using the Paris public transit system with the majority of the network wheelchair accessible.