Now, I'm not a photography specialist at all, so it may well be that a lot of what I say here is either already wellknown or simply wrong: feel free to use the reply option below to post any corrections or additions of course.
The photographer is François Félix Fescourt (1817-1881), from Nîmes. He starts working as a photographer around 1860, it is unknown what he did before. While he also worked as a portrait photographer, he is now mainly remembered for two things: a series of stereoscopic images of the Roman ruins in and around Nîmes, and a booklet (about postcard-sized) of photos of the same, with an explanatory text on the back of each image.
His large size images of the ruins seem to be much less known though; of the twelve, I could find five which were elsewhere attributed to him (either like this, or in a smaller format only), and five which were known but not attributed to him: the other two seem to be completely unknown.
In at least two cases, unsigned works by Fescourt were attributed to Édouard Baldus (1813-1889), a much better known and highly sought after early photographer who photographed many of the same locations, often in a very similar way.
Catawiki sold the above image of the Arena of Nîmes as "attributed to Baldus" for 220 Euro last year.
Similarly, one of the unknown photos, a stunning view of the Pont du Gard, resembles the work of Baldus as well.
Remarkable in that second image is that the background has been, well, photoshopped; the Maison Carrée is surrounded by houses, but looks better without them. This again is something Fescourt seems to have copied from Baldus, as can be seen in this image from the Metropolitan Museum collection.
An image of the cathedral of Nîmes is known at Ribapix, but again without the name of the artist and with a slightly too late date.
The other 15 images, for which I sadly haven't found the artists, are in somewhat worse condition overall, and seem to range from the 1850s to ca. 1900. A real specialist should take a look at them presumably.
