Pension fund managers from the Netherlands to Canada, searching for new ways to invest, lambasted private equity executives at a conference in Paris this week for charging excessive fees.

Ruulke Bagijn, chief investment officer for private markets at Dutch pension manager PGGM, said a Dutch pension fund for nurses and social workers that she invests for, paid more than €400 million ($501.6 million) to private equity firms in 2013. The amount accounted for half the fees paid by the PFZW pension fund, even though private equity firms managed just 6% of its assets last year, she said.