Topic summary
Enforceable

Extracted from the Wikipedia article Unenforceable.
Prostitution
Sometimes, contracts may be enforceable one way and unenforceable the other way. Again, there is an example from the field of prostitution. In Germany, where prostitution is also legal, a law exists that – once a contract has been entered into – makes a prostitute's demands for payment legally enforceable (even via collection agencies and courts if necessary), but the client's demands for fulfillment of the contract and rendition of sexual services would be unenforceable. German lawmakers made only the claims of prostitutes enforceable because they intended for German prostitution law to protect only prostitutes, without helping or furthering the interests of buyers of sexual services.