Such stipulations do not violate personal rights, the North Rhine-Westphalia state labour court said.
The case addressed a dispute over an employment agreement by a company that conducted airport passenger security checks under a federal police contract.
According to the controversial clauses in the documents, workers must wear either bras (white or nude-coloured) or undershirts “to preserve the orderly appearance of employer-provided uniforms,” the court said.
The court also found no fault with requiring fingernails to be shorter than half a centimetres to protect passengers from injury.
Employees can also justly be forced to maintain “hair that is always clean, never worn looking unwashed or oily,” and require men to be clean-shaven or have a well-groomed beard.
But the company will no longer be allowed to dictate which shade of nail polish or hair colour employees choose, the court ruled.