The Clarins Instant Smooth Perfecting Touch is a makeup primer that claims to "provide a fine, melting texture that conceals lines, pores, and imperfections in an instant". As someone with rather big pores around my nose and forehead, this sounds like a rather promising base. A small tub came in the Clarins It Kit I bought last year but I honestly haven't reached for this a lot due to my fear of silicone based face primers.
The slightly pink cream feels very thick and almost waxy and I hypothesized that silicones made up most of the ingredients. According to Sephora, the following chemicals are present in the Instant Smooth Perfecting Touch:
Cyclopentasiloxane, Dimethicone, Dimethicone/Vinyl Dimethicone Crosspolymer, Hydrogenated Vegetable Oil, Vinyl Dimethicone/Methicone Silsesquioxane Crosspolymer, Silica, Disteardimonium Hectorite, Pentaerythrityl Tetraisostearate, Alcohol, Tocopheryl Acetate, Butylene Glycol, Silica Dimethyl Silylate, Acacia Senegal Gum, Phenoxyethanol, Caprylyl Glycol, Hexylene Glycol, Ci 77019/Mica, Ci 77491/Iron Oxide, Ci 77891/Titanium Dioxide, Ci 75470/Carmine.
As you can see, silicones definitely comprise the bulk of the ingredients. I prefer water based primers such as Laura Mercier's Foundation Primer because they glide on a lot better and sink into the skin rather than sitting atop the pores.
On my sometimes dehydrated skin, the Clarins primer emphasized my dry spots and flakes appeared on my cheeks. My foundation went applied well over top though and after my skin produced some natural oils, the dryness eased and didn't seem to be a problem. The primer did nothing out of the ordinary for me and while it does reduce the appearance of small pores and very fine lines, it's not a favorite.