Germany's male prisoners must have the same rights as female convicts to spend money on cosmetics and phone calls, the Constitutional Court has ruled.
The verdict came after a male inmate appealed against a prison policy, describing it as gender discrimination.
Until now, only women were allowed to spend up to 30 euros (£25) of their jail income each month on cosmetics and 25 euros (£21) on using the phone.
The male prisoner who won the appeal was not identified.
"Although the interest in cosmetics may be more widespread or frequently stronger among women than among men, it is not a biologically determined interest among women," the Karlsruhe-based court said.
It said the current practice of only allowing women to purchase beauty products amounted to a violation of the protection against sex discrimination under Germany's Basic Law.
"Members of one sex cannot be denied their cosmetics choices simply because they are more typically found among the opposite sex."
But the court said phone calls may be denied to inmates for security reasons.
The male prisoner had decided to appeal after being refused requests to have the same rights to spend money on phone calls and beauty products as female inmates.
Officials at the undisclosed prison had argued that the men's wing did not have a secure room for the telephone, and that only women needed to shop for cosmetics.
The prisoner's lawyer, Kai Zimmermann, told the AFP news agency that his client had fought for "the right to use aftershave, moisturiser and the like".