RER B and Metro transfer in Paris

You can change to the RER D either at Nord or at Les Halles. Your ticket will be a zonal magnetic strip ticket, and you will need it to exit the station at Gare de Lyon. CDG is in zone 5 and everything in central Paris is in Zone 1, that defines the price of the ticket. You don't really want to switch to the Metro system, as that will involve walking around the underground tunnels trying to locate the right line. But there is no reason you can't. Your RER ticket will get you anywhere on the Metro in central Paris.

Or you can change to RER A at Chatelet les Halles. I think that Line like A runs more frequently than Line D. Either way, as the other responder said, connection from one RER train to another is easier than finding the metro. Are you committed to the metro? If not, consider the Air France bus service to Gare de Lyon (www.lescarsairfrance.com), which costs a little more than the RER.

This can be confusing the first time. The RER is metered so you use your ticket to both enter and exit since different trips cost different amounts. The metro is one size fits all and there is no use of the ticket at exit.

So what this means coming in from CDG is that you use your ticket (9.75) CDG-Paris to enter the RER at the airport putting it in the turnstile which stamps it. When you arrive at Nord you will put the ticket through an exit turnstile of the RER and then re-insert it into the metro turnstile. The machinery will 'know' you are on a continuing trip and accept it. If it doesn't see an agent who will get you through -- they can read the ticket and know it is valid.

If you are transferring to line 2, the exit and entrance turnstiles are fairly close together on the corridor between Nord and La Chapelle metro. I can't recall how close together they are on the other lines which are accessed at Nord downstairs. The metro stations are very clearly signed at each station and you will just follow the signs for your line.

Be sure to keep your ticket until you exit at your final destination as you can be checked for a valid ticket at any time and if you cannot produce a validated ticket then you pay an on the spot rather hefty fine. Enforcement has stepped up in recent years. We went years only being checked once and then in the last 3 or 4 have been ticket checked several times on each trip.

I am also traveling from Paris CDG Airport to Gare de Lyon. It looks like it is possible to transfer from RER B at Gare du Nord to RER D. Is that connection correct? If so, does anyone know how easy it is to transfer from RER B to RER D at Gare du Nord? One platform I saw mentioned that RER D is just across the platform from RER B, but another wrote that I would have to look for signs to the platform for RER D. What is correct!?