It's not a howitzer it's a 75mm Mle 1897 field gun. The guy in the suit in the bottom image is the Director of Inventions Jules Louis Breton -
a very important figure in the development of French armaments during WW1. There is a video of trials of the Renault SPG on one of the French
archive websites (just can't find the URL at the moment). The Renault SPG was also fitted with a 105mm Schneider Mle 1913 but it wasn't accepted with either gun.
