Federer, 36, won the Swiss Indoors title in Basel on Sunday – then withdrew from the Paris event hours later.
There are more ranking points up for grabs in Paris than Basel – the former is an ATP Masters 1000 event while the latter is a 500 – but Federer remains unbothered.
That’s incensed Forget, who says the French supporters have now been snubbed twice by the 19-time Grand Slam champion.
That follows Federer’s decision to skip the clay-court season and not play at Roland Garros.
Forget told l’Equipe: “Roger’s French fans will be disappointed because he missed Roland-Garros as he trained four hours a day because he was preparing the grass.
“These are choices that we have to accept, but when we love the beautiful game, and God knows if there are many people in France who like to see Roger play on the field, well they will have to watch it on TV or in another event.
“I believed [he would play] until the end. I am very disappointed – on the one hand as a lover of the beautiful game and especially as a tournament director.
“Many people are making efforts to best accommodate all the best players in the world. There are a number.
“Our tournament, like two years ago, is better when the eight Masters players are present here in Paris.”
Although Forget is taking some solace in the fact Rafael Nadal is in action in Paris.
He added: “I think Nadal will sketch a small smile. The players who had to meet him will be a little relieved.
“Lucas Pouille will take Federer’s place in the draw.
“There are extremely talented players. There is Zverev who is world number 4, who may be Roger Federer of tomorrow.”