This is a Sachs-Huret Rival ARIS ATB rebranded as the Regina Enduro 1992.
The Sachs-Huret Rival ARIS is a presentable, solidly constructed and reasonably effective unit. It has its cable clamp bolt mounted on a sprung arm - to give what Shimano called a 'light action'.
In fact, compared to a Shimano Light Action derailleur of the time, the Sachs-Huret Rival ARIS was just slightly later to market, just slightly more expensive, just slightly heavier and indexed with just slightly less accuracy. It's cruel to say so, but it was also just slightly uglier.
It's tough competing against a highly capable, 800 pound, gorilla like Shimano.
This example displays the following features:
As a Regina branded component, there is no 'Sachs-Huret' logo on the pulley wheels and no writing at all on the rear parallelogram plate.
All the internet blather, that I can find, points to the Regina Enduro 1992 being released in ..., wait for it, 1992. By this date Sachs-Huret had replaced this design, and were allowing Regina to adopt an outdated model.
And, god, that pulley cage is gruesome - whoever designed that thing? And, more to the point, who agreed to pay them? The inner pulley cage plate is so large you could serve a three course meal on it.