When you are asking help to people around, it is more common to use "direction", and possibly use a gesture to indicate the direction. - Pour (aller à) Paris, c'est bien la bonne direction ? [To (go to) Paris, this it the good direction, right ?] Angie response is also good, but I find it more natural not to inverse verb and subject in the question and put a tonic accent on word *bien*. - Je suis bien sur la bonne route pour aller à Paris ? [(unheard : do you confirm that) I am on the right way to go to Paris ?]

hello ! Yes, you are right; "etre sur la bonne voie" is used in a more general sense (e.g. if you are solving a maths problem) ; the english equivalent would be , I think "to be on the right track" . You undertook something, there is still some work to be done, but you do it the right way, using the right method,so there is little doubt that you will succeed shortly. About asking about the right way ; you can simply say "Paris, c'est bien par là ? " (and you show the direction with your hand) ; ou Je veux aller à Paris, est-ce que je vais dans la bonne direction ?" ou " Quel est le chemin le plus simple (le plus court) pour aller à Paris ?"'

If your are lost in a station, you could ask too: Quel est le bon trajet pour aller à Paris? ou Quel train dois je prendre pour aller à Paris?

suis_je sur le bon chemin?