The independent Appeal Committee was chaired by Professor Lorne Crerar (Scotland) and also comprised of HHJ Jeff Blackett (England) and Russell Howell (Wales).
It was the view of the independent Appeal Committee that the original Disciplinary Committee was in error in its determination that the offence was deliberate and of the top end in the level of seriousness.
The Appeal Committee found that Flannery had stamped on Julien Bonnaire recklessly rather than deliberately and accordingly determined that the offence was of mid-range in the level of seriousness.
The incident occurred on January 13 when Munster played Clermont Auvergne in the Heineken Cup's pool stages at Parc des Sports Marcel-Michelin.
Having taken into account any mitigating and aggravating factors, the Appeal Committee reduced the period of suspension from eight to four weeks which will now run up to Thursday, February 21.
That means that Flannery, if selected, will be free to play for Ireland against Scotland on February 23, Wales on March 8 and England on March 15. He will also be available for Munster's Magners League match away to Cardiff Blues on March 1.
Commenting on today's decision, the Limerick man said: "I am really delighted with the outcome. I've known in my heart and soul that I never deliberately stamped on him (Bonnaire). It is really important to find that this is affirmed by the Appeal Committee.
"I am very grateful that the ERC handled this appeal with such expediancy. I am hugely appreciative of the support I received, and for the representation made on my behalf by the Munster management and legal team led by Donal Spring."