When I cycled from Paris to Le Bourget I just took the most direct route straight up the N2 from Porte de la Villette to the airfield and museum of Le Bourget, a distance of seven or eight kilometers. This was quick but not very nice, so if I ever do this again I think I will try to find some better route.
My photo shows the beginning of the town of Le Bourget, which is not a terribly attractive place to cycle to or through.
By the way, the highway N2 in Le Bourget is called Avenue du 8 Mai 1945, because the Second World War ended on that day — or it might have ended on May 7 or May 9, depending on who you ask. All you loyal readers of my post on the Surrender Museum in Reims might recall that the first capitulation was signed there on May 7, 1945.