Possible tenant stating no pet fee

[Mike Flora]

I have a possible tenant stating they do not have to pay a non refundable pet fee to have two small dogs live with them in our property because they are therapy dogs for her dad of which she is the caretaker for. To my understanding of this, which I will ask my lawyer about but wanted to see what you guys say, I cannot discriminate against my possible tenants and I'm not by charging a pet fee. I'm not denying them a chance to submit an application and rent out the property whatsoever, but since there are dogs they need to pay the fee. This is in Riverside county of California. Anyone else deal with this before?