Gare du Nord to Gare du Lyon

The local transportation would not normally take more than 20 minutes (RER green line D or taxi), but Gare de Lyon is large and takes time to navigate. Train schedules suggested by DB allow 70 minutes connection time, which would be a better bet. There are fast trains about hourly to Dijon, but if you miss a reserved train, your ticket won't be good on another one.

I've never heard of the RER in Paris being referred to by colour.

It is the RER-D. The whole sum of two stops.

Yes, it is true that Gare de Lyon is very large. Some platforms have alphabet names, A,B,C, etc., others numbers, and they are a fair distance apart.

Make the connection? Probably. Comfortably? Depends on your definition of comfort and how slow your group moves.

thanks for the prompt replies

I would call 55 minutes perhaps doable, but not comfortable. Especially since you'll be needing to find your way off the first train, to the metro signs, down into the metro, stand in line to buy tickets, await your train, take it a few stops, then change at Bastille (which involves quite some steps changing from Line 5 to Line 1 in that direction, nothing too bad but depends on size of your luggage), then arriving at Gare de Lyon and finding your train and getting on it.

In fact, I know my way around both of those train stations and the Bastille metro station, and I'm not sure I would try it.

I guess it would depend on how much I had invested in the onward Dijon ticket, and how comfortable I would be buying new tickets on the spot if I didn't make the train I was aiming for. That's your own comfort level to consider.

EDIT TO SAY: aha, the suggestion about the RER Line D could work too, but I don't know that it really saves that much time. You have to go so much further deeper and the system to me is more confusing, but it might be fine.

The RER D (green on the Paris Metro map) is direct and takes 7 minutes. There will be elevators and escalators to access the platforms at both ends, and there are 4 trains every half hour.
The issue is:
The schedule mid day is the trains leave at 00, 06, 12, 27 past the hour and the half hour. As you can see, there is a 15 minute gap between the 12 and 27 departures, so you need to plan that you could hit that gap. So if it takes you 15 minutes to get off the train, find the RER D entrance, buy tickets (from a machine) and get to the platform, 15 minutes waiting for the next train, 7 minutes travel, 15 minutes to get off the train, make your way up to the station level, locate your track and walk out and board the train. That comes to 52 minutes, giving you 3 minutes of slack. So use the bathroom on the train before it pulls into Nord.

Richard, it is RER line D. The signs are not colour-coded.
Watch this video (only 2 minutes): https://www.youtube.com/watch?t=2&v=RSAHTKVBVwg
Then read this page: http://seat61.com/Paris-metro.htm
Tickets cost €1.80 You should be able to do it in about 30 minutes, including all the corridors you have to walk along.

RER D definitely. A friend did it in ten minutes but from Gare de Lyon to Gare du Nord to join us for a trip north. It will be longer for you because Gare de Lyon is more confusing, as Nigel says. Get as far forward in the train before arriving at Gare du Nord so you have less crowded platform to walk. At Gare du Nord, you only have to make it onto the last car to be in the train.

Hi,

Another choice you have in getting from Gare du Nord to Gare de Lyon is the bus. Several buses stop at Nord in front of the station and on Rue St. Quentin. Take bus # 65 at Nord to Gare de Lyon. Catch that Rue St Quentin in front of the Chinese restaurant. I've done it both ways, taking the RER D and bus #65. But with your time constraint better with the RER D.

The signs are, in fact, color-coded. I was on the RERD the other day . . . and noticed the green . . .and there's the red RERA and the blue RERB and the yellow RERC . . .

I absolutely defer to our local expert. I'd never noticed RER signs being coloured, but if they are, more's the better.

Certainly the coloured lines on the map have been there as long as I can remember, which has got to be over 40 years...

Thanks for all of the advice. I think , being a senior citizen, I will take the RER D but will make one reservation to Paris and then one from Paris to Dijon leaving myself a couple of hours to make the connection. The video btw was great.