No, that is not a good deal because Rail Europe doesn't offer discount fares. If you book well in advance (up to three months allowed) on the TGV Europe site, you can get a DEPART fare as low as €55 for a bunk in a 6-person couchette (which is what you would get for your $119/person fare from Rail Europe) and €85 for a bunk in a 4-person couchette. To keep the site in English and to keep from being bumped to the Rail Europe site, choose Great Britain as both your country of residence and the country in which you will retrieve your tickets. You will be able to pick up your tickets at any SNCF station or boutique (shop) in France, even though you originally chose Great Britain.
For a description of this night train, including photos of the sleeping accommodations, go here.