Hape was cited by French match commissioner Yves Thieffine for the tackle on Edinburgh back-row forward David Denton last Saturday.
Irish star Hape cannot play again until December 15, meaning he will miss Heineken Cup games against Cardiff Blues and Racing Metro, plus Aviva Premiership appointments with Wasps and Saracens.
Hape, who signed for Irish from their Premiership rivals Bath earlier this year, pleaded guilty to the offence at a hearing on Thursday, when Exiles rugby director Toby Booth and team manager Kieran McCarthy made representations on his behalf.
Hape was reported for being in contravention of Law 10.4 (e) - "dangerous tackling of an opponent, including a tackle or an attempted tackle above the line of the shoulders even if the tackle starts below the line of the shoulders."
Judicial officer Robert Williams upheld the citing complaint and decided the offence was mid-range in terms of its seriousness level with entry point of six weeks.
"When considering aggravating factors, the judicial officer added one week," said European Rugby Cup, in a statement.
"Having then taken into account mitigating factors, including the player's guilty plea, clean record and clear remorse, the judicial officer reduced the period of suspension by the maximum amount of 50 per cent.
"As suspensions are rounded up to whole weeks, the player was suspended for a period of four weeks."
Hape has the right of appeal, but his absence for two European games is a blow to Irish, who are already on the back foot in terms of qualifying from their pool following a narrow home defeat against Edinburgh.
Meanwhile, Perpignan's French centre David Marty has been banned for four weeks after admitting to a dangerous tackle on Exeter wing Gonzalo Camacho during the second half of their Amlin Challenge Cup clash last Friday.
Marty pleaded guilty of a lift tackle in violation of law 10.4 (j), which carries a ban of up to six weeks.
Marty will be available again from Thursday, December 15.