Agélou (Jean) & Cie, rue Armand Gauthier 1 et 6, Paris, and
Agélou (G), 5 & 7 (2nd floor) galerie Vivienne, Paris
Jean Agélou was a photographer before becoming involved with postcards,
initially with marks JA and ABM. I have put the ABM marque as a separate entry as the examples I have of children may be from a previous owner. ABM 344 Le Baiser (not shown) is more like Agélou, it shows a semi-naked couple embracing.
There are many photos of nudes under the JA, Lydia, and Léo marques.
Nudes with the STL logo (which occurs with variations) have also been ascribed to him.
Jean continued to find the models and take the photographs after his brother George took over the business side of things.
Both brothers died in 1921 in a car accident, George aged 42. See for example in Wikepedia.
The Léo marque was then taken up by another publisher, not obvious why as the customer base must have changed a lot, and this site takes you to the successors for that marque.