As you said, there are 3 varieties of Marans recognized by the APA in the US. But they are Black Copper, Wheaten and White. No blue on the list.
In France there are 8 recognized varieties but no blue on that list either. They are Silver Cuckoo, Golden Cuckoo, White, Coppered Black, Black, Wheat, Black-tailed Fawn, and Ermine.
I didn't say anything about the APA I just said blue marans. You stand corrected.