Katharina Tofeji alleged that the investment bank had refused to grant her a four-day working week after she had a baby.
Tofeji, who worked in the foreign exchange unit, claimed she was treated badly after announcing her pregnancy in November 2004.
The tribunal heard her appraisals and bonuses did not reflect that she had been outperforming colleagues. Before returning to work after maternity leave she applied for a four-day working week – but this was refused.
On her return, Tofeji claimed she experienced a hostile reception and general surprise among her colleagues that she had decided to come back after her maternity leave.
But the central London employment tribunal dismissed her claims, ruling that she was not wrongfully dismissed and was not treated less favourably than her male colleagues.
Tofeji said she was “very disappointed” with the judgment. Her lawyers said they were reviewing the decision to determine whether to appeal.
The bank said in a statement: “BNP Paribas is pleased that all claims against it brought by former employee, Ms Tofeji, have been unsuccessful. BNP Paribas and its current and former employees have been totally vindicated and the allegations made have been found to be unsubstantiated.”