I was left an original etching by Henri Jourdain, how do I find out what it is worth and where and who do I contact to sell it?

One thing to do in order to get a start on finding out the value of it, would be to look on the Internet for similar items by the artist that already have or will be sold. Here is one such search. Looking for similar items on eBay is one way. Henri Jourdain eBay - Google Search

Another way is the following image search. Henri Jourdain - Google Image Search

You also might want to click on the questions that have been similar to yours on the bottom of this page and see what the answers have been. It is possible that Henri Jourdain's works were part of those that were a part of the Paris Etching Society. A link to information about that society is contained on the following link. https://www.askmehelpdesk.com/art/par...ad-155531.html

Other possible resources for you would be people at an art gallery, teachers of art at a high school, college or university, books on art that are available at public libraries and bookstores, and, asking an auctioneer.

Ultimately, what a work of art is worth in monetary value depends on what someone is willing to pay for it.

If you want to sell it, you could use one of the many sites that are available to list things free of charge. If you click on the following search, you will find many links to sites where you can list what you are wanting to sell.

Free Online Classifieds - Google Search