Agriculture Minister Pierre Paradis has been removed from cabinet and suspended from the Liberal party.
Philippe Couillard made the move after the Sureté du Quebec informed the Premier he is the subject of a police investigation.
Laurent Lessard has taken over as Agriculture Minister; he will continue his duties as Transportation Minister.
The Premier's office was made aware of some type of allegation against Paradis in the past few days, but Philippe Couillard only made the decision to relieve the Minister of his duties and remove him from the Liberal caucus late Thursday.
While the Premier did not mention the nature of the investigation involving Paradis, multiple reports say he was recently involved in a fight in Quebec City and someone had filed a sexual misconduct complaint with the municipal police force.
The Sureté du Quebec would not confirm the reports.
Paradis has been on sick leave after falling while horseback riding and suffering a concussion.
The 66-year-old has represented the riding of Brome-Missisquoi since 1980.