Manager charging $1 to change shift at restaurant. Money goes to...

My manager started charging $1 to change shifts at a restaurant. Money goes to the employee Christmas fund. Is this illegal? If so what law does it break? It bothers me and I want to complain but I do not know if I have any legal grounds.

Thank you for your input. Sincerely!

This is an Irish site. The law, custom and practice would be different.

Brendan