The man, whose identity was not revealed, was said to be brooding after he got the haircut in Bremen on Wednesday. He left at first but was so annoyed he decided to return, police said.
The man then allegedly walked up to his 52-year-old hairdresser, sprayed him and then showed him his middle finger. He was said to have legged it afterwards but the police quickly caught up with him and he was arrested.
A staff member, 23, was apparently hurt after being caught in the cross fire of the pepper spray. The man is facing an assault charge and may also get done for contravening the Explosives Act after police found a firecracker in his possession.