Upvote:1
As far as I know, there is no airside transfer between Terminal 3 and any other terminal (Terminal 3 is the low cost terminal for charter flights and very low cost carriers — even EasyJet don’t use it).
You will have to deplane, go through immigration, reclaim your bags, go through customs, transfer to Terminal 3 (a bit of a walk + CDGVAL + more walk) and check-in before the deadline (probably depends on the airline, but often 1 hour).
Depending on exactly which terminal you arrive at, your citizenship and status, whether you have checked luggage or not, and more, it could range from barely OK to very very tight if the incoming flight is on time. Quickly impossible if there are any delays.
Also since this connection is nearly certainly on two separate tickets, remember that if you don’t make the check-in/baggage drop deadline for the second flight, they will consider you a no-show, cancel your ticket (and possibly subsequent flights on the same ticket, depending on the airline), and you’ll be on the hook to book and pay for a new ticket (at the last minute, so usually quite a bit more expensive).
If you haven’t booked yet or still have the option to change either flight, I would strongly recommend rebooking with a lot more margin.