Paris Metro Line 12 or 13 to Gare Montparnasse coming from the north?

Are you staying between Guy Moquet and Lamarck - Caulaincourt? I'd take line 12. But I'd take 12 over 13 anyway because I have never been on 13 and it was not packed and I mean packed. Then again, I have not taken the metro in Paris since 2018 so things could have improved. Which trip will have more stops? I've never gotten off Line 13 or Line 12 at Montparnasse Bienvenue so I don't know how the walk is between the the area of the metro station where the trains stop and the long-distance train station. I'd be interested in knowing if there is a real difference.

FWIW

https://www.lonelyplanet.com/articles/unofficial-map-shows-walking-distances-between-paris-metro-stations

Thanks. Not too concerned with crowds and stops per se - it will be a Saturday morning so about the same ride times 12 or 13.

Walking map is interesting, and we are big walkers, but not from Montmartre to Mont Parnasse with bags.

Out of lines 12 and 13, which one get closer to Gare Monparnasse? Or the same?

Line 13 is closer. The 12/4 station is on the other side of the Tour Montparnasse skyscraper from the train station. If I recall correctly, there is a moving walkway for at least part of the way. You could see that clearly from the old Metro Geo map, but I don't think they publish it any more. Fortunately, I still have it saved on my computer.

Thanks Sam!

Yes, Sam is correct, lines 6 and 13 run just under the northern edge of Gare Montparnasse and, connected by a long passageway, lines 4 and 12 are located under blvd Montparnasse.

The passageway from Line 12 is LONG. Walking from the metro platform to the train station concourse takes a solid 10 minutes with luggage.
Therefore, line 13 is my recommendation here!

Same as what Sam, Tocard, and Balso have explained so well !!