I'm usually a little disappointed when people ask for ID's and don't provide pictures, but I'm doing the same thing.

Was walking in a local cemetery where exotics are common. I came across a maple which puzzled me. Most maples in this area have already flowered a while back, and are showing mainly keys. This one had rather large (4 inches or more) hanging clusters of flowers - kind of like a panicle, with a few immature keys forming. From pictures I perused on the internet, the flowers looked most like Acer macrophyllum, though the leaves and other characteristics were different, and I doubt if that species is planted here.

The two halves of the still tiny (maybe 3/4" ) keys were very upright. In some the tops actually overlapped, others created a narrow U shape between the two halves.

The leaves showed some similarities to sugar maple (5 lobes)but the edges were a little more toothed (like maybe red maple). Their size was comparable to those two species, though they may not have been fully open. The petioles were a couple or few inches long and green - no hint of red.

Bark is hard to describe, this one was fairly non-descript. I am quite familiar with Sugar Norway Silver and Red maple bark and this didn't look like those species. If anything strikes you as a possibility I would appreciate hearing it. I may try to get back with pics.