With that leaf shape and color, I would guess an Acer platanoides seedling, Norway maple. One of the few maples that naturally offers up something other than green as a leaf color and freely self-seeds to the point of almost being considered an invasive species.

Slender shoots, general leaf shape and pale undersides = silver maple. Otherwise if leaf shape not exactly right for silver maple then Freeman maple, the hybrid between silver and red maples that comes up on its own where the two parent species are present. (And a seedling of a Freeman maple - named selections of this hybrid are very frequently planted - that happened to result from pollination by one of the parental species would then represent a third genetic combination, such as A. saccharinum x (A. rubrum x A. saccharinum)).

Here is a close up of the leave, the bark is smooth and reddish brown. Thank you for your ( very knowledgable ) replies !!!

Silver maple/ freeman maple, not Norway maple. I don't think they are very common with redish leaves.