As in you can subtract it from your taxable income, I assume. I think it's fairly normal (in this part of the world*).

In germany and poland.

Yes, you pay income taxes (and insurances) on all membership fees like gym (about 50%). If you put money into union, and union pays your gym fees, you save tons of money.

But there is tons of legal bs around unions. You need to structure it, like you are promoting socialism, and only reason to go into gym, is to smash capitalism!