Good Afternoon,

Based on your description, it sounds like the tree is infected with maple leaf tar spot, known scientifically as species of Rhytisma fungi. Leaves that are infected with this fungal disease have round, light green to yellowish-green areas approximately ½ to 1 inch in diameter that eventually blacken. Heavily infested trees may lose their leaves prematurely. Trees infected with maple leaf tar spot are unsightly, but the fungal disease does not affect the overall health of the plants. Fungal spores can overwinter; therefore, it is important to remove all leaves as soon as they fall to lessen the impact of the disease next year. Because maple leaf tar spot is primarily a cosmetic disease, fungicide treatments are usually not necessary.  

If this isn't what you think it is please send some photos and I can try to help diagnose.  

Why do my maple leaves have spots?! - MSU Extension

Maple Diseases (psu.edu)

I hope this helps.  Thanks for using our service.