Given that the nearest place for you to buy N°7 cosmetics is the UK, you will not be brokenhearted to read this review. It seems to me that this product concentrates too much on shine prevention than the actual skin priming for the foundation (it cost 10 $, 40 ml, it costs 11 £ in the UK).
First of all, the consistency is thick, white in colour and it dries super fast on your skin, leaving white streaks all over the face unless you apply it really thinly and in small amount. You definitely need to moisturize your skin in advance.
When I applied the primer, I started to feel an unpleasant tingling sensation, which I put down to the fact that it is going to be blocking the excess oil. Moreover, my skin looked pale, patchy and felt dry and grainy. Undeterred, I still finished my makeup and went to work.
The itching did not stop and naturally, the oil in the skin started to fight its way through the cakey layer I put on in the morning. Horrified, I removed all the foundation.
I've done a research, and usually they recommend moisturizing the skin, applying thin layers only to the T-zone and blend well. However, this did no work for me so I would not repurchase this product.