There was an experimental network in France before the Transpaq network of the minitel that was designed for inter-connectivity. It strongly inspired TCP/IP which is, in my opinion, what actually created the Internet of today (having a world-wide network of networks). https://en.m.wikipedia.org/wiki/CYCLADES

I don't think the vision of the minitel was to build an international network though, so there might not have been much interest in inter-connectivity I guess.