Oh, he was very well known in USSR / Russia in the late 80s / early 90s. My friend was a DJ on a radio station back then, and she once played his music for an entire night -- and got a call from a listener who thanked her and said that it changed his life.

As for his present-day popularity among younger people, it isn't as high as that of, for example, Queen or Pink Floyd -- though I had a ride with a young Uber driver who was entranced with Les Chants Magnétiques that we heard playing on the car radio.

And as for me personally, I currently have three of his songs in my Spotify favorites.