taxi:
A taxi is a painless way to cross Paris, especially if you have large amounts of luggage. A taxi from the Gare du Nord to (for example) the Gare de Lyon or Gare d'Austerlitz costs around 17-19 euro and takes about 25 minutes.
However, be aware that there's often a long queue for taxis at the Gare du Nord and other main stations, so always allow at least an hour or preferably more between trains, see above. Don't accept taxis from touts, use the official taxi rank at the side entrance to the Gare du Nord (the same side of the station as the Eurostar platforms). Make sure the driver turns the meter on when you drive off.
Pre-booking a taxi...
As there's often a long queue for taxis at the Gare du Nord and other Paris stations, it's a good idea to pre-book one. Several companies offer pre-bookable taxis in Paris, including
www.taxis-g7.com. To book a taxi from G7:
Call the G7 Taxis English-speaking line on +33 1 41 27 66 99. Lines open 24 hours.
Bookings can be made from 7 days until 1 hour before you need the taxi.
A credit card guarantee may be required at certain peak times.
Book the taxi for at least 10-15 minutes after the scheduled arrival of your Eurostar. They'll give you a booking reference. The taxi will wait up to 5 minutes if you don't turn up on time (you may be charged for the waiting time!).
For some reason, their taxis can't or won't use the official station taxi ranks, so at the Gare du Nord they will normally tell you that the taxi will wait at 12, Boulevard du Denain, across the road directly opposite the front of the station. Similarly, if you're being picked up at the Gare de Lyon, ask to be picked up at number 2, Place Louis Arnand, which is outside the Hotel Mercure, just walk outside the station onto the forecourt and turn left. The taxis have a 'G7' sticker inside the rear window (see the photo to the right).
If you tell them you're arriving by train, some G7 staff will refuse to book a taxi for you and tell you to call back on the day of travel. In fact, I suspect these staff are following their company policy, whereas other staff happily conspire with you to pre-book one, using an address that doesn't look like a station pick-up (which may explain the point above!). So it's probably better to avoid mentioning that you're arriving by train, use the '12, Boulevard du Denain' address above instead of mentioning the Gare du Nord, and if the staff member refuses to book a taxi because they suspect you're arriving by train, either (a) politely insist on pre-booking a pick up from one of the above addresses instead of the 'Gare du Nord' or 'Gare de Lyon', as it may be the reluctance to pick up from stations that's the problem, or (b) put the phone down, re-dial and get a more helpful member of staff who will pre-book it for you. Yes, you really can pre-book one of their taxis, but some G7 staff are more helpful than others in getting around their company's rather self-defeating and hazy rules about train-related taxi bookings...
Of course, you could call G7 Taxis on the day of travel using your mobile once your Eurostar exits the Channel Tunnel, and then you'll be sure you've reached France running on time. That might a good option!
You just pay the taxi driver at the end of the journey in the normal way, based on what the meter says, around 17-19 euros from Gare du Nord to the Gare de Lyon, Gare de Bercy or Gare d'Austerlitz, plus the 5 euro booking fee. The drivers accept both cash (euro) and credit cards. A recent Gare de Lyon to Gare du Nord trip cost 25 euro including the booking fee and a five minute wait as we were a bit late.
If you use this service, feedback would be very welcome. It's reported that they may not accept taxi bookings during the Paris rush-hour.
Alternatively, go to www.taxi-paris.net (+33 6 07 60 49 14, tim@taxi-paris.net) and book a hassle-free private transfer specifically designed to meet trains and take you across Paris to board another train. This service gets good reports, with an English-speaking driver meeting you at the Eurostar arrival gate with his car parked right outside the station. The only downside is the cost, around 58 euro per car plus 1 euro per luggage item, 4th & 5th passengers a few euro extra. They may ask for a 50% deposit. If you use this service, feedback would be very welcome.