England prop Joe Marler will face an anxious wait to see whether he will be hit with another disciplinary hearing after appearing to kick Grenoble hooker Arnaud Heguy in the head.

Harlequins romped past Grenoble 30-6 at The Stoop on Friday night to reach the European Challenge Cup final, but that three-try win was overshadowed by England prop Marler.

The 25-year-old was in his first game back after his two-match ban for the “Gypsy boy” slur against Samson Lee in the Six Nations, but found himself in hot water again thanks to the 26th-minute tussle with Heguy.

European bosses have 48 hours from the end of the match to bring a citing against Marler, and any ban could leave him a doubt for England’s June tour to Australia.

“Any test for a citing has to pass the red card test, and this does not pass that test,” said Harlequins boss Conor O’Shea.

“Should he do it? No. Is it a red card? No. It’s disappointing to have to talk about it because I thought his scrummaging was excellent.

“But he is under the microscope.

“Things happen, we never condone it but if that is a red card there’s a heck of a lot of things that happen on the pitch that are worse.”

Citing commissioner Iain Goodall will now determine whether Marler should face a disciplinary hearing for the incident.

Jamie Roberts, Nick Evans and George Lowe claimed the tries that sent Quins into their first European final since 2011, where they will face the winners of Saturday’s Montpellier-Newport Dragons clash.

O’Shea’s side could yet be without Marler for the final in Lyon on May 13 if he does face another suspension.

Marler initially escaped censure for his taunts against prop Lee in England’s 25-21 Six Nations victory over Wales at Twickenham on March 12.

Global governing body World Rugby later intervened and called a misconduct hearing however, dissatisfied with the leniency of Six Nations and RFU bosses.

Marler admitted the charge and was banned for two matches and fined STG20,000 ($A37,000).

The loosehead prop had only just returned from that suspension for Quins’ last-four European tussle at The Stoop on Friday night, and has appeared to waste little time in courting further controversy.

“When you’re a marked man you’re a marked man,” said O’Shea.

“People probably look more for things when Joe Marler’s involved than with others, but that’s life.”