Here is the common red-leaved variety of Norway Maple. It is widely planted as a "lawn tree.".
Early spring flower cluster.
Close-up view of the flowers.
Here is a comparison of a Norway Maple leaf with that of Sugar Maple (Acer saccharum). The Sugar Maple leaf is on the bottom. Note that the Norway Maple leaf has more points than the Sugar Maple leaf. The sure way to tell them apart is that Norway Maple has milky sap. This is most readily seen by breaking a leaf stalk. It's the only maple to have milky sap.