It’s a JAEGER form the early -60thies.
Clavis box doesn’t have the same marks as yours on the inside.
So probably yours don’t have the same size/case.
And Reverso’s was smaller then the chronos back then.
Plus there was not many around at that time.
You said it’s not an extra ordinary watch…
Phu…
Sorry Nicolas – I give up, please show us!!!
Best
Blomman