In our experience, no, it isn’t easy! Many stations do not have escalators or elevators, particularly outside the centre of Paris, and there can be a lot of walking and stairs. Be prepared to drag bags up and down stairs.
The trains themselves do not have space set aside for luggage and they can be very crowded, making it difficult to get on and off with luggage. It is best to avoid travelling at peak times (approximately 08h00 – 10h00 and 17h00 – 20h00).
You may be lucky and someone will stop to help you but don’t bank on it and be aware that staff will almost certainly not assist you (also, be careful of people being very pushy to assist as they may have ulterior motives).
Therefore, if you have luggage and may physically struggle, are travelling with children, or have a lot of luggage we suggest taking a private transfer instead (for longer journeys like from the airport into Paris) or catching a taxi* or Uber. (Note that most Paris taxis do not accept credit cards.)
*Be careful of scam artist taxis at trains stations and airports who charge excessive prices. You want to look for taxis at the official taxi stands with a proper meter and a taxi sign on top. They should not approach you inside airports or train stations.