I think it's fairly standard code in most cities that any branches of a tree in a neighbor's yard that overhang yours can be trimmed back to the property lines.
We did that last fall. The house behind us, a rental, has an enormous weeping willow tree. Its branches overhung our yard by a good 15', they overhang out next-door neighbor's yardby 20' and the house next to the rental on that street by probably 30'. The landlord lives 100 miles away and doesn't give a rat's.
We got a tree maintenance company, who was working in the neighborhood, to come in and cut off everything that overhung the fence lines of our property. What a difference - we even get the evening sun in areas where it never reached before. We're looking forward to actually being able to grow things in that corner of the yard this year. $350 well spent.