I can easily do the living composers part. Less easy is the "not 'too' atonal" part.
So I'll take your "if possible" as an out.

First, I'd like to mention Pierre Henry, who died a couple of years ago. I saw him in concert shortly before that. He looked really sick. I've been listening to a lot of his music recently as part of my comprehensive ripping exercise. It's a lot better than I remembered it.
Anyway, on to the list:
Francis Dhomont (1926- ) An important early pioneer of French electroacoustic music. Taught for many years in Montréal.
Éliane Radigue (1932- ) Prominent French electroacoustic minimalist. (No, not the pattern or repetition type.)
Michèle Bokanowski (1943- ) Known mostly for her music for husband Patrick's avant-garde films. But only mostly.
Jérome Noetinger (1966- ) Electroacoustic improviser and composer. Often works with Lionel Marchetti (1967- ).
There are many more, of course, especially if you include French-Canadian composers, who are easy to include if only because Dhomont taught in Montréal for so many years. (Gilles Gobeil (1954- ) for instance.) But you've probably got enough on your plate to last you for a couple months or so....