Thanks roue l'an for the information.
We have always either walked or used the metro, but are keen to try the buses on our next trip.

Excellent post, and is encouraging me to take buses on my upcoming trip to Paris.

Usually I walk until my feet bleed, and then take taxis

I have avoided using the Metro for the last few visits, as, because I live in London, it makes me feel like I am in work! Even here, I will plan the extra time and take buses where I can and its sensible. Of course in London that is NOT recommended if going from one side of London to another, even without heavy traffic.

You can only transfer to a bus going in the same direction, within 90 minutes.
You are not allowed to go in the opposite direction, or change bus lines.
If you want to do this, you'll need to use a new advance ticket.

The new Paris bus routes are almost finalized now. Starting in September 2018 about 30 lines will be taking some different itineraries. Some of them are being shockingly shortened at one end and extended at the other, generally into the suburbs since there is more to the world than just Paris.

If you want to check the interactive map, you can just click on any line number and it will show you the current route in gray and the new route in red. Just click on 'retour à la liste' when you want to see another line.

http://paris.grand-paris-des-bus.fr/...e-interactive/

Thanks for the link, kerouac.