Looks like a Freeman maple. Which would explain the flat samara....some cultivars of this hybrid will produce no fruit.

Are you sure that isn't an Acer truncatum x A. platanoides cross like Pacific Sunset or a similar cultivar? The leaf and samara seem closer to Norway maple to me, but I could be wrong. Bark is also darker and less smooth than what you typically see with young Freeman maples.

https://landscapeplants.oregonstate.edu/plants/acer-pacific-sunset

Norway maple, unless it is one of the Keith Warren (of J Frank Schmidt nursery) hybrids mentioned in preceding post.

Shooting from the hip I would have just said Norway maple before those were brought up.

Where trees asked about are located geographically affects identifications. as what is present varies regionally. If you submit anymore mystery trees later be sure to include this information, for best possible results.

I thought the sinuses seemed too deep and rounded for the leaf to be that of just a Norway maple. Fall color could help with the identification as well. Norway maples usually just turn a pale or ruddy yellow. The Acer truncatum hybrids are often brilliant with oranges and reds.

The location of the OP/tree would definitely help. I can tell you with certainty that the hybrids are not hardy here in the upper Midwest while Norway maples are fairly common.

Hi, i found them in Melbourne, Australia. Obviously not native, they were being used as a street tree. This probably doesn't help :)

I believe they turn a yellow in autumn.