My family is traveling from DFW to CDG, then connecting flight CDG (terminal 2E) to MAA and holding Indian passport. The existing US visa is expired.
There are transiting in between terminal 2E to catch up another flight.
Do they need to have Transit Visa?
As shown in this previous answer, the situation is complex and ambiguous.
For most people, you don't need to have a visa or transit visa when you stay "airside", i.e. both your flights are on the same ticket, and you can just go from one gate to another (possibly going through security), without going through immigration passport control, baggage claim, customs, and exit passport control.
But there are a few exceptions where an "Airport Transit Visa" is required even in this situation, depending on the airport/country where you transit, and your citizenship. In the general case, Indian citizens need such an ATV to transit through french airports, including CDG.
There are however a few exemptions from this rule, and that's where it gets complicated:
Both Timatic (the database used by the airlines to determine what documents are required before they will let you board) and the legal basis for Airport Transit Visas (the Schengen Visa Code aka CE810/2009) state that if you have a US visa, even if it is expired, and are returning to India, you don't need an ATV.
The official french website on the topic, however, does not list this exemption, and says only valid US visas allow you to transit through CDG without an ATV.
Since the only check should be the one done by the airline before you board in the US, and they should base their decisions on Timatic, and Timatic says you don't need an ATV in your case, you should not need one.
However, if you want to stay on the safe side and avoid any possible issues because someone has a different interpretation, then you should either:
