France Info radio says the three employees, two black men and and a woman of Asian origin say that Guerlain made racist remarks on 24 February at the Gare du Nord in Paris.
Guerlain uses a wheelchair and he had arrived late for his train and was refused access to his carriage.
The three employees say he became annoyed and said "France is a shit country, this is a shit company and what's more the staff are all immigrants".
The three employees remarked that they "are just as French" as Guerlain.
Guerlain is already on trial on charges of racism in connection with other comments made on French television.
In October 2010 when he was interviewed by public television channel France 2 about how he created the Samsara scent.
Guerlain replied using the French term "negre" and implied that black people are lazy.
"For once, I set to work like a negro. I don't know if negroes have always worked like that, but anyway..." he said.
The incident sparked widespread condemnation, with anti-racism groups saying it highlighted deep prejudice in French society.
Yesterday Jean-Paul Guerlain, for decades the "nose" of the world-famous perfume brand, told a court he was not racist and that his comment about black people being lazy was a stupid joke.
"I very deeply regret (the remarks) and I offer my apologies to the black community for this idiocy," he told the Paris court. "I wanted to make the journalist laugh and I regret it."
"I am anything but racist," said the 75-year-old, who is heir to one of the world's oldest perfume houses.
If found guilty he faces up to six months in prison and a 22,500 euro fine.
Guerlain apologised but protests erupted outside the company's boutique on the Champs Elysees in Paris and there were calls for a boycott of Guerlain and its owner, luxury brand giant Louis Vuitton Moet Hennessy (LVMH).
The Guerlain company also distanced itself from the remarks, saying his words were "unacceptable" and noting that Guerlain had not been a shareholder since 1996 or on salary since his retirement in 2002.
LVMH purchased the company in 1994 and Guerlain remained as master perfumer
until he retired.