I don't think she is a Marans...American or French. If French line, she would have feathered legs (down outside of leg, down outside toe). If American line, she would be clean legged.
It's hard to tell in just the one photos, but she just doesn't have the "upright" Marans appearance to me. They stand a bit taller than the regular flock member (from the Langshan in their background).
Her coloring is more of a Black Sex Link as well, especially the lacing on her chest. Even "brassy" Black Copper Marans hens don't have that kind of mottled laced appearance. Her legs would be all dark grey/black down to her toes as well. Her soles should be pinkish white that shows inbetween the toes. Below you can see my FBCM hens of several years ago. (Sorry I don't have better photos).
At any rate, she is fully mature and should be laying. Look for a taupe colored egg as most of my BSL lay that color.
LofMc
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