If you don't mind taking the metro with your bags, take RER B from CDG to Châtelet Les Halles or Denfert Rochereau, then transfer to Metro line 4 to Montparnasse.
This site is run by Ivar at in Santiago de Compostela.
This site participates in the Amazon Affiliate program, designed to provide a means for Ivar to earn fees by linking to Amazon