Mac address collection through an Android application

I am working on an android app and when an user registers an account, I want to collect his mac address in order to restrict the login for the specific user only on that device.
I need a system that does not allow the sharing of the account between several people in any circumstances. I use firebase authentication, but I haven’t found anything useful to help me prevent this.

Is it legal to collect the mac address in Europe ?

Source: Android Questions