Huma - A French-Swiss brand

It takes a 16mm band for sure. Don't remember the exact diameter but 30mm sounds correct.
The second hand is missing and there's a dent and scrape on the bezel indicating a hit the original crystal couldn't have survived. It keeps fairly good time and winds and sets just fine. I figure it was damaged when fairly new then repaired, lubed and a new crystal installed not too long before I got it. I think this is one of those I picked up for around 10 USD or less off Ebay.
I haven't opened it up to examine the movement yet. Been leaving well enough alone for now. I would not be surprised to find it has a movement identical except for marking to your Huma.
There are advertisements in old comic books and magazines for watches that look to be identical at very low prices, boy sized compared to the style of men's watches at the time. I have several of the smaller case watches from 26mm to 33.5. Due to a childhood accident my left wrist is a bit undersized so smaller watches are more comfortable for me.