transportation from Gare du Nord into Paris

If you're packing light and don't mind schlepping your bags, the cheapest would be the Metro/RER (€1.40). Assuming you mean the Boulevard Saint-Germain, if you want specific directions, you need to give the either the name or the address of the hotel. It's a fairly long street. However, a taxi wouldn't be very expensive since it would be a relatively short ride.

Thanks Tim. The hotel is La Maison St-Germaine and it is at 158 Bd St-Germaine. I think the taxi route might be better. Would they take all 4 of us (2 teens) and 4 plus bags or would we need a van?

You can take Metro line 4 (direction Porte d'Orleans) directly from Gare du Nord to the Saint-Germain des Pres station and walk from there.

Paris taxis include minivans as well as sedans. Just ask for one at the taxi rank outside Gare du Nord.

Note: Saint-Germain does not have an "e" at the end.

As long as you don't have more than 1 medium-size bag and 1 small carry on per person you may be able to get everybody into a regular taxi. Four of us recently took a taxi from our hotel in the 15th to Gare St-Lazare and we were able to fit in a regular sedan, luggage and all. (And you haven't lived until you've watched a Parisian taxi driver navigate through morning rush hour -- one of the most memorable -- if nail-biting -- experiences of our trip!)

I believe taxis charge 1 Euro per bag also, Rick's Paris book may have more info on this. But I have taken taxis from Gare du Nord several times. For me, it's the most sane way to get into Paris from here. And the Parisian drivers are definitely a trip!