Neighbor building balcony

California
My neighbor is building a balcony in his backyard that gives them a
> direct view into my upstairs bedroom and invades my privacy when I'm
> in my backyard. Is there anything I can do.

Normally not too much except change your structure or landscape to avoid them.

But check city codes; they may violate a local rule and ask the city building inspectors and code compliance to comment. You could also threaten a lawsuit arguing it is a material and unnecessary damage to your home and property use--and that there are other ways they could build. Even the threat of a suit may cause them to reconsider.

[sunlover]

Close your curtains when dressing. What are you doing in your backyard that you dont want seen?