Two of France's most influential investor lobby groups are worried about plans to restrict soft commissions and split brokerage fees paid by institutional investors.

The regulator, AMF, will publish its recommendations next month for unbundling research and trading costs inspired by the findings of the UK Myners report. But the AFG asset management association and AFEI, the French society for brokers and investors, are worried the new rules fall foul of the law of unintended consequences.