Ingredients: It's a physical sunscreen with Zinc Oxide and Titanium Dioxide providing protection, in a mostly silicone base.
Texture: it's a thickish white cream.
The other hand, without sunscreen, for comparison.
The Dr Sebagh gives a very matte finish; it's actually too matte for my skin in the winter and I found my skin was a bit dry on my forehead and cheeks by the end of the day, even with moisturiser layered underneath. I also found that I had to cleanse very carefully to remove it all; it required a thorough massage with a balm or oil cleanser to remove it.
Summary: this isn't for me for everyday use, but an oilier skin might get on very well with it. I'd use in high summer if I was going to be outside a lot on any particular day, but for everyday summer use with only incidental sun exposure I will stick with the Chantecaille Firming Sun Cream.
Dr Sebagh is available at Selfridges and Space NK.
Disclosure: samples provided by PR for brand without charge.