What does it mean that someone managed to live beyond 120 years? God Himself limited a human's lifespan to 120 years, as told in the following verse:


  Genesis 6:3 (NLT)
  3 Then the LORD said, “My Spirit will not put up with humans for such a long time, for they are only mortal flesh. In the future, their normal lifespan will be no more than 120 years.”


Yet, Jeanne Calment managed to live for 122 years and 164 days, significantly more than 120 years. Does this mean that God's decree was somehow part of an old order of things that has since passed away or been overwritten, much like what Jesus did with the Law?
While marc-gravell mentions that the 120 years until the flood interpretation is "hotly contested" I would say that is definitely the best interpretation. Even the link provided by Marc really talks more about the timeline for building the ark rather than contesting the "120 years to the flood" interpretation. The author of that article concludes that this is the best interpretation of Genesis 6:3.

If we take 120 years to as some average lifespan then the Bible completely misses this mark. Immediately following the flood the lifespans are still measured in the hundreds of years and by the end of the patriarchal period the lifespans drop well below a 120 year average. The main issue with interpreting this number as the years until the flood only occurs with the length of time it took Noah to build the ark. When we realize that the text doesn't require that Noah started building at the same year as the statement in 6:3 then the interpretation works rather well.

The problem stems from the poor translation of the NLT text. In attempting to make the text more "readable" they have inferred meaning that isn't required by the original text. Most (all?) scholarly translations do not force this meaning into the text of Genesis 6:3.