Her lawyer Petra Laback told dpa on Wednesday that the case began after her client visited a public toilet with a male friend and wondered why she had to pay while he did not.
"This really got under her skin," the lawyer said.
The 27-year-old woman filed a lawsuit at a district court a week ago, and the city administration now has the opportunity to file an objection.
If no objection is raised, Laback expects damages of 1000 euros ($A1,639) to be awarded to her client.
"My client is not in it for the money. She would donate the sum," Laback said.
The plaintiff also emphasises this on a dedicated website she has set up to encourage other women to follow her example.
"My aim is that such injustices come to an end," she writes.
The city sees the matter differently.
Of the 167 public toilet facilities it operates, 27 charge a fee for cubicles, according to a statement by Vienna's administration.
In these high-traffic facilities, external cleaning staff are permanently deployed during service hours.
"This ensures that the facilities can be used without issue," the statement said.
During hours when staff are not present, a large proportion of these toilet facilities are also available free of charge.
In a similar case, Austria's Federal Equal Treatment Commission ruled in 2010 that no direct discrimination had taken place as using a toilet cubicle costs both sexes the same fee.
It saw a distinction between providing a toilet cubicle and providing a urinal.
