Private Equity owned - this translates into short term objectives, which don't make sense from a business viewpoint, but only from a financial one. Leaves the impression that the bride is prepared for the wedding.
Very high turnover - brain drain.
Jobs are relocated from Europe to the US, leading to the impression that Paris will become a pure development shop (was once the headquarter).
Management doesn't understand performance measurement industry needs. Most of them worked for data vendors prior to joining the company.
Lack of people management skills (not necesarrily true for the developper teams): poor to no communication at all with direct managers, absence of clear and realistic targets. Little to no recognition for delivered work.
Work contracts & engagements are not respected and subject to modification once you've signed your initial contract (bonus payments & commissions for sales related activities)