Yes, it is RER B line that go to CDG without changing to Subway or another RER line.

This is one of the reason I was looking at this hotel for my trip next year.

-- Added --
From Google Maps, it show as 7 min walk from Laplace RER station to the hotel. So with bags / luggages might take 10 min or so.

https://maps.google.ca/maps?saddr=Co...a=ltm&t=m&z=17