Amusingly, I learned about Minitel just a few hours ago when I stumbled upon this video from John Stossel's show (obligatory thanks to YouTube algorithm) where he mentions Minitel as an exhibit of government/public sector's failure to innovate and a way for the French government to 'control the growth' of this new technology before private players. Here's the video (with the exact time stamp) where Mr. Stossel talks about Minitel -- https://youtu.be/rOkkqoDJl-s?t=208
I then searched the web (through Google) for information on Minitel and this IEEE article showed up.