I have been looking at Georges Rouard and his shop/gallery/workshop A La Paix, Paris and came across this thread.
From
https://www.art-angelux.com/rouard...using google translate ”....But it was in 1900 that he [Rouard] took over at 34 avenue de l'Opéra in Paris, the management of the auction house ‘A la Paix’, founded twenty years earlier by Jules Mabut.”
There’s a bit more further down that suggests Jules Mabut was ‘custodian of Gallé productions’ and others.
So possibly just an auction house/retailer.