Five men are still missing, presumed dead, after the 15-metre longliner, Kleine Familie, sank 15 miles north-west of Alderney on Thursday morning.
The hull of the wooden Cherbourg-registered vessel was painted green.
The French authorities revealed on Saturday that divers had found the paint on a ten-metre section of the hull, below the water line, of the chemical carrier Sichem Pandora, which was in the area off Alderney when the fishermen were lost.
The ship was on her way from Malta to the Netherlands in high seas on Thursday, but was escorted into Dunkirk later the same day, where the captain was questioned and the boat examined.
French authorities also announced on Saturday that a mini-submarine operated by the French navy had located the wreckage of the fishing boat on the sea bed.