Hollande would reportedly arrive at the flat on a chauffeur-driven scooter and had fresh croissants delivered to the love nest in the mornings by his personal bodyguards.
The Socialist leader has slammed Closer's report as an outrageous attack on his right to a private life and said he is considering legal action.
But he has not denied the substance of the magazine's claims of a passionate affair which pushed him and Gayet to take "insane risks."
French media reaction to the Closer report had largely been subdued and a poll published on Sunday suggested that more than three quarters (77 per cent) of French voters think the president's love life is nobody's business but his own.
But any hopes Hollande harboured of riding out the storm were shattered as opposition MPs started to try and make political capital out of his embarrassment.
Jean-Francois Cope, the leader of the centre-right UMP, said Hollande was holding the presidential office up to ridicule and questioned his judgement.
"You only have to read the international press. When they talk about France at the moment it is either about this affair, or about (anti-Semitic comedian) Dieudonne," Cope said.
He said the Closer revelations should act as a "lesson in humility" for Hollande.
"When you are President of the Republic you have to be very careful about all these questions. Everyone regrets the publication of these photos but that is how it is, that is the society we live in."
Who is now the first lady of France?
Another UMP deputy, Daniel Fasquelle, questioned whether it was "normal" for Trierweiler, who has her own personal staff within the Elysee, to be financed by taxpayers while Hollande was carrying on with other women.
"The French may ask themselves: who is now the first lady of France?" Fasquelle said in a tweet.
Trierweiler, 48, is a glamorous, twice-divorced career journalist who has three children of her own and has been Hollande's partner for the best part of a decade.
Exactly when they became a couple is unclear but most accounts of his turbulent love life concur that he left Segolene Royal, a fellow heavyweight in the Socialist Party and the mother of his four children, in 2005.
In public he was still pretending to be with Royal two years later when she ran unsuccessfully as the Socialists' presidential candidate.
Biographers claim he dithered for months over which woman he should be with and the charge of chronic indecisiveness is one that has returned to haunt him in office as he has slumped to the lowest approval ratings of any French leader in living memory.
The only bright note for him is that pollsters do not see the suggestion that he may have been cheating on his long-term girlfriend as having any impact on his standing with the electorate.
"In fact he is already so unpopular that this will not change anything," Frederic Dabi of pollsters Ifop told the Journal du Dimanche newspaper.
Hollande is due to give an extended press conference on Tuesday at which he was expected to elaborate on a New Year message that has been interpreted as signalling a change of direction by his government towards more business friendly policies.
That event now looks certain to be overshadowed by the turmoil in his private life.
Trierweiler has herself endured a torrid time since entering the Elysee alongside Hollande in the summer of 2012.
At the time she boldly declared that she intended to redefine the role of first lady to the point that they'd have to come up with an alternative term.
An appearance in spiky high heels and a thigh-revealing dress prompted Britain's Daily Mail to exclaim that she was the real star attraction in the couple, the epitome of the "effortless Parisian chic that makes French women the envy of the world."
Within a few weeks however Trierweiler's feisty temperament had got her into hot water.
Reportedly enraged by Hollande having maintained warm relations with Royal, Trierweiler sent out a tweet backing a renegade Socialist candidate who was up against her lover's ex in a battle for a parliamentary seat.
The rebel won and Trierweiler was publicly rebuked by Hollande while his four children reportedly stopped talking to her.
A string of articles and books have portrayed the Paris Match journalist as a tempestuous, jealous personality who keeps Hollande on a tight leash and polls have suggested two thirds of voters have a negative opinion of her.
- AFP
