I have a very nice piece of Art with Paris etching society (top right) with a signiture that looks like b Moru in the bottom left and another signiture Louis Parrib (I think) in bottom left, it is a nature scene with a small water fall

Here's my usual C&P on this subject:


One of the best resources that I have found concerning Paris Etching Society is from Google answers, located HERE (http://answers.google.com/answers/threadview?id=39718).
The response from scriptor-ga is very insightful.

Basically PES was set up by Sidney Z. Lucas, hence the SZL mark. He owned a printshop in New York in the years 1940 to 1960 where He
produced a large number of prints after old etchings.
Generally, prints by Mr. Lucas seem not to reach very high prices.
At the end of the day they look nice, but that's about it.
Most of what is talked about them is from people "boiler rooming" the price on the supposed French history.

I hope this helps.