RATP website says tickets are good for 90 minutes on the bus, from the time your ticket is first validated to the last. No apparent limit on the number of transfers allowed, no roundtrips, and no getting off and then back on the same bus.

My question is this: can you get off one bus, piddle around a bit like picking something up at a shop, then get on another bus (different route no.) as long as it's within the 90 minute timeframe? And are there any restrictions as to which bus routes you can transfer between?

Where I live transfers are extremely restricted, you are only allowed to make them at exact intersecting points with no lag time in between. You're out of luck if you try to board even one stop away from the closest intersecting stop. Am I right in thinking this isn't the case in Paris?

I'm curious to hear answers to this. If it can be done, I wasn't aware of it.

I can't swear to it, but I don't think there are any restrictions on which bus stop or connecting line you can get on -- as long as it isn't the same one you got off, and as long as it's within the 90 minutes.

So if you want to walk a block or two and then get on a bus line on that street, I think it's just as valid as getting on a bus line closest to where you got off.

We often stop to buy a bottle of water or even grab a quick coffee and haven't had a problem.

My husband and I shared a carnet in September. Curiously, once in a while, when we went to validate our tickets on the second bus, one or the other got a red light. But, the bus driver would just initial them for us.

Please help a bus-challenged fellow traveler here! Do I understand this correctly?

You get on a Paris bus, cancel your ticket in the machine, but hang on to it. 10 minutes later you get off, walk around, board another bus 15 minutes after that. Do you insert the already-cancelled ticket in the machine?

I know, I probably sound like a dummy. But we always use a new ticket and take no account of trip time. Can this really be done?

yes, I think so -- the machine on the bus can actually tell what bus you were on before, so that's why they can regulate that you can't get back on the same bus

Be aware that transfers are only possible with the new t+ ticket which you can buy in carnets or as single tickets at Metro and RER stations. If you buy a ticket from a bus driver, it will be good for one ride only.

There are new metro tickets - "t+".

With the new tickets, you can transfer on the buses using the same ticket for up to 90 minutes.

These new tickets are issued in the metro, but if you purchase a carnet at a Tabac, for example, make SURE they have the "t+" on them. (We got a carnet we had to exchange last year, but perhaps the tabacs have all run out of the "old" ones.)

Also, you cannot transfer on the same ticket if you purchase your ticket on the bus.

So long as you have a "t+" ticket, you validate your ticket on the first bus. If you look at your ticket right before changing hands, etc., it will have an imprint on the underside with the bus route number, etc. If you remember to turn your ticket around when you board the next bus and validate it, it will print on the other side of the bottom. Otherwise, it will print over the previous imprint.

I'm sure these imprints are in case you are asked to show your ticket to an inspector.

Obviously, if you transfer more than once, or insert the ticket in the same direction every time, you will have one imprint on top of another.

If your 90 minutes are up, or you've wandered too far off a reasonable transfer, you'll get a red light (or yellow?) instead of a green light when you attempt to validate it on the next bus. But, sometimes it's rejected in error and the bus driver will "validate" it for you with a pen.

Is this an interchangeable metro/bus ticket like the old ones? Does the t+ ticket cost more?

Yes, the t+ ticket can be used anywhere the Metro goes, on the RER in zone 1, on buses, on trams (except for T4), and on the Montmartre funicular. You can transfer between bus and tram but not between bus and Metro. The fare is 1.50€.

And a carnet costs 11.10€.