In the last few years, I've been going to many meetup groups in Lyon. Finding a meetup is really easy to find these days. Meetup has a lot to do with this as it makes group creation and promotion accessible. Anyone can create a group and benefit from Meetup's recommendations to attract potentially interested people.
Even though Meetup is a paid service, its ease of use and its AI are part of its success. It has a vibrant and diverse community and the name "Meetup" quickly became part of common vocabulary. Meetups are very popular and Meetup.com suggests at least one new group every week, and most of those groups really are of interest.
Lyon may be a small European city but has this real advantage that it is small enough for all to be able to come to meetups and big enough to have a fair number of groups. Top that with a booming tech ecosystem and there's just no excuse not to go out and learn something new and contribute.
Meetups definitely got me regularly into new techs and getting to know people I would never have seen this quickly in my day-to-day work. It's a great opportunity, on I can't miss on. Best of all, practically all of these meetups are free.