The France international, 26, was taken in by Kent police last Thursday after a woman in her 30s alleged she had been assaulted at an address in Fulham, London, on Monday, 6 May.
A Metropolitan police spokesman said: "Officers from Sapphire (a unit specialising in rape and sexual assault investigations) are investigating an allegation of rape which happened on 6 May in the west London area.
"The allegation was passed on to the MPS by Kent Police on 8 May after the 34-year-old female victim reported it to them on the previous day. The victim alleges she was raped by three men.
"On the morning of Wednesday, 15 May three men, (A) aged 26; (B) aged 23; (C) 22 yrs, were arrested at an address in Fulham on suspicion of rape - they remain in custody at a west London police station."
In a statement, QPR said:"The club is aware of the allegations regarding Loic Remy, but due to police investigations is unable to comment."