It’s possible that the history of Romet (and ZZR) goes something like this...

In 1948 the new communist government in Poland nationalised the major bicycle manufacturers, amalgamating them into a single company, possibly called ZZR. This company ended up with a motley assortment of factories in Bydgoszcz, Poznań and Czechowice-Dziedzice. During this process, ZZR may have had something to do with (or grown out of) Pafaro.

By 1953 this company had decided that its main bicycle brand would be called Romet and that its main bicycle manufacturing facility would be in Bydgoszcz.

At the peak 1.2 million Romet bicycles were produced a year, and they were exported in significant quantities to the west (I seem to remember some particularly horrible small wheel and folding bicycles). However, within its product range Romet included decent quality racing bikes and even track bikes.

One website comments that, for many years in Poland, a Romet bicycle was the typical present that god-parents gave to their god-children on their first communion - it’s always good to work god into your marketing mix.

Following the collapse of communism in Poland, Romet was reorganised as a public limited company in 1991, but was not able to compete and the bicycle manufacturing arm went bankrupt in 1998. It is possible that a component manufacturing arm survived, possibly making Romet cranksets.

In 2007 a new company, Arkus & Romet restarted the manufacture of Romet brand bikes, although I do not believe it has anything in common with the old company except the brand name and logo. This company is possibly based in Debica.

In terms of derailleurs, I have examples two basic Romet designs. The first is a dead ringer for a Huret Svelto. This derailleur started life carrying the ZZR brand, but was rebranded as a Romet in 1977.

The second Romet derailleur design is the Tornado - possibly dating from 1989.