Vadim Vasilyev told Sky Sports News in October last year that Monaco would wait until at least the end of the 2017-18 season before allowing Lemar to leave.
Monaco's stance did not change despite Liverpool's sale of Philippe Coutinho to Barcelona prompting reports Lemar could make a switch to Anfield earlier than expected.
Arsene Wenger also denied Arsenal would make another attempt to sign Lemar - who turned down a £92m move to Arsenal last summer - before Wednesday's deadline.
"He will stay at Monaco until the end of the season 100 per cent," Vasilyev told RMC, a French radio station.