The Torah presents a case of a "Mosi Shem Ra" (one who gives a bad name), in which a husband accuses his bride of not being a Betulah (virgin). In the event that the accusation is proven false, the husband is fined 100 coins as a penalty for besmirching a Jewish maiden.
The Terumat HaDeshen (R. Yisrael Isserlin, 1390-1460, Austria, Siman 307) was asked about applying this Halacha to the following case. Reuven, a Chazzan in a Bet Knesset, was accused by Shimon of being a Noef (adulterer). In light of these charges, the community removed him from his position and hired a new Chazzan in his stead. Eventually, the accusations were proven false. Reuven sought to regain his position, but it was already filled by the new Chazzan. Reuven then sued Shimon for damages as compensation for losing his job.
While logic might tell you that Reuven is entitled to compensation, the Terumat HaDeshen rules that he is not liable. The precedent of "Mosi Shem Ra," presented by the Torah is a special case that only applies to accusations made by a husband regarding his wife. Clearly, Shimon violated many prohibitions, and Reuven is not obligated to forgive him. However, although there are no monetary damages, Bet Din is permitted to impose a "Knas" (fine) on Shimon to create a deterrent in the community and prevent this type of injustice from happening again.