The six were detained and questioned at Grenoble police station following a complaint by a young woman that she had been raped by the players after meeting them at a nightclub following their Top 14 match against Bordeaux-Belges on March 11.
Bordeaux police investigating the complaint were dispatched to Grenoble to carry out the questioning of the players who arrived at the Grenoble police station at around 8:40 am (0740 GMT) on Wednesday.
Three were accompanied by lawyers while the other three were apparently not represented and entered the police station through a back door.
A lawyer for for one of the Irish players said her client was "serene" after being questioned for around two and a half hours.
"This was an evening between consenting young people and important elements will appear during the day," she was quoted by regional daily Le Dauphine Libere as saying.
Police also questioned Grenoble club official Michel Martinez for two hours at the police station as a witness, the Dauphine Libere newspaper reported.
It said several other Grenoble club officials and players were also expected to be questioned during the day as witnesses.
On Friday Grenoble took the decision to sack the players facing accusations of drugging and raping a girl they met in a nightclub, the struggling French Top 14 side said.
"In order to avoid any confusion between the investigation, which concerns individual and private behaviour, and Grenoble Rugby club, we have decided to immediately lay off the players concerned as a precautionary measure," the club said in a statement, without giving any details.
The alleged victim of the attack told police she met several Grenoble players in a nightclub last Saturday night after the club's Top 14 defeat in Bordeaux.
She said that some of them drugged her and then "forced her to go to a hotel where she was raped," local media reported.
Grenoble club president Eric Pilaud previously told AFP that "if the case is confirmed, it's serious".
He added that he "felt sick" at the idea that a rape had taken place.
In a statement the club said "it had total confidence in the legal system, while at the same time respecting the concept of presumption of innocence."
It added that it would not be making any further comment until the investigation was concluded as it "did not want to interfere" with the inquiry.
Anglo rugby players in France have been making headlines for all the wrong reasons in recent weeks.