According to BBC Togo's official election body declared President Faure Gnassingbe the winner, with a provisional 59% of the vote.
Mr Fabre, who gained 35%, told AFP news agency the results were a "crime against national sovereignty".
Observers from the African Union said the election was free and fair.
Mr Fabre called on the Togolese to "take their destiny into their own hands". BBC reports.
President Faure Gnassingbe's family has ruled Togo for 48 years.
Mr Gnassingbe has ruled since the 2005 death of his father, Gnassingbe Eyadema.
According to BBC reports, On Monday Mr Fabre called for a delay in announcing the results, citing widespread irregularities.
Last year, opposition protests failed to bring about constitutional changes limiting the president to two terms in office - a move that would have prevented Mr Gnassingbe from standing.