The ugly blunt bow is on all the Mistral class - not sure why, must ask naval architect sister....
Just conjecture, but reading up on the original design from which the Mistral was developed there was a problem with turbulence over the deck around the superstructure which would affect helicopter operations. They had a lot of wind tunnel tests and altered the design.
Is it a possibility that the flat prow acts the same way the blunt nose is used on air vehicles to lift the airflow above and away from the deck?