Featured tortoiseshell cigar case- French antique？

I checked, it is just north of the Wadden Sea. The culture and language are the same as on the Wadden Sea islands though, Frisian.

 

You hold it horizontally.
One half to present cigarettes to others, the other for your own use (chain smoker)?

Ditto, that is odd.

 

My Dad had a cigarette case like the ones in Komo's post. It had horizontal sprung metal holders that were fascinating to me. IIRC it had a cartouche on the front with his initial engraved.