Are the 10-packs 10 single rides that can be used among 2 people?
If you manage to purchase physical paper ticket booklets of 10 tickets from a Metro/RER ticket window, yes you can share these tickets amongst several people. Very soon though these booklets of paper tickets will disappear. By Sept 21, 2023 the Paris transit authority will complete their phase out of paper Paris Metro ticket booklets completely. Most Metro/RER station ticket windows already no longer sell booklets of paper tickets. And all automated ticket machines have already stopped selling booklets of tickets (since Oct 13, 2022).
Click on Phase 3 of this map to see which Paris Metro stations no longer sell paper booklets of tickets from their ticket windows. Stations that are not highlighted with their name in green, will still sell booklets of paper Metro tickets from their ticket windows.
If the 10-pack of tickets is put onto a Navigo Easy, each person will need their own card since passback is not possible (card & ticket can't be validated in short succession at the same station or bus).