Maple tree

Sorry Newatthis, I’ve never been able to grow a maple here as it’s too windy. It looks like black spot fungus to me.

It could be Tar spot, a fungus. There is little you can and although unsightly it does not affect the tree.
In order to control the spread any fallen leaves should be picked up immediately.
We had something similar on our pear tree. We were unable to spray it, but left it for two seasons not picking the fruit and sweeping up all the fallen leaves. It seems to have recovered by fighting the fungus with its own immunity.

I agree tar spot. The tree will probably lose it’s leaves early as well. As J52 says rake up any fallen leaves which should be burnt.