It was a much larger, integrated, nationwide network. It's more comparable to compu-serv than any BBS.
It also had an integrated terminal that was way cheaper than the microcomputer + modem setup you needed to connect to any of the American services or BBSes, and as a result it had better market penetration in France.
Technically, of course, it wasn't anything special. But it was a great example of an early online service that was useable for non-technical people.
It had better market penetration because the terminals were free. FTA, they tried the same service in Ireland, without the subsidies, and market penetration was nil. It was a dismal failure.
It also had an integrated terminal that was way cheaper than the microcomputer + modem setup you needed to connect to any of the American services or BBSes, and as a result it had better market penetration in France.
Technically, of course, it wasn't anything special. But it was a great example of an early online service that was useable for non-technical people.
EDIT: PS: The Computer Chronicles did an episode on Minitel: http://archive.org/details/frenchtech1