France here. I do take my bike everywhere (RER, TER, TGV… I've never had a car and rented <10x in my life, at 37 y-o). But it's getting difficult to find/book a place in most fast trains, especially between Paris and Loire Valley as there are too few racks available and biking is becoming more popular. I wish all major train stations had 24/7 bike renting service, including for bikepacking.