There are many valid points made above. I don't think there was a design flaw, but frankly, I haven't spent enough time reviewing the aircraft's specifications and performance over it's lifespan.
A brief note regarding France, her civil system, and politics. The French hate (absolutely HATE) being wrong about anything. Those that I have met and worked with, generally speaking, are disporortionally arrogant about themselves and their country's place in the world. I have no trouble believing that a concerted effort was made to ignore evidence that would tend to make France look bad. Thus, blame it on Continental - a US company.