What is harassment and what is not?
Sometimes, things aren't clear... Can we trust the allegations? It might just be a disagreement between 2 persons? Where is the frontier between occasional or even involuntary wrong behavior and harassment? The definition of harassment is quite clear. But the identification of harassment situations is sometimes uneasy.
Use a professional to help you identify whether the allegations are serious and what actions are required.
How to react?
It is your duties as Employer to provide a clear policy indicating what your employees should do in case they feel victim of workplace harassment or in case they witness acts of workplace harassment. The policy will include indication of who to report those facts to, in which format, indication of the protection of the victim or witness against retaliations and what support is available to them.