The workers at Change stores in Sweden said they are required to list the information on their name tags and wear them at all times while working, The Local reported Tuesday.
"We have dirty old men coming into the shop looking at my cup size. Why should everyone get to know that? Guys selling underwear don't have to show their size," an employee said on condition of anonymity.
Change Chief Executive Officer Susann Haglund said listing the employees' sizes was an idea from workers and is an optional measure.
However, workers said they were told the tags were mandatory and they are issued demerits if they are not wearing them with all information visible when mystery shoppers come into the store.
The Commercial Employees' Union said it is suing Change for discrimination after negotiations fell apart. A union spokeswoman said officials are looking into whether the name tags are a violation of Swedish law.