Telecom, like many grande école, has a lot of clubs and associations for all hobbies and all tastes. You can find descriptions of the main ones on the BDE site : https://bde.telecom-paris.fr/assosclubs
Some clubs are not present in this list but you will know about them because of their events during the year (stay tuned on the Facebook group “admis” to know about everything coming up).
There is also a “forum des associations” at the beginning of the year where you can meet the members and collect t-shirts and goodies from different clubs (Don’t miss it!)
You can always decide to open a club of your choice, you just have to ask the BDE who will probably accept!