These were found around 1990 in a bed in the Esterel area, but that is the limit of the info I have on them. They are distinctly different to anything else I have seen from the area though and they show that there is more going on in the Esterel area than we generally know.
Small Esterel with Silicified Mud
Esterel Thunderegg with Banded Agate.
Specimen of Esterel Seam Agate/Thunderegg
Small Red Esterel Specimen from an Unknown Location