Fan returned at Amazon, very very very fast refund (upon deposit of the parcel at the post office!), I finally bought a first prize fan, which is even less noisy than the Rowenta costing 3x the price!
So to have minimal ventilation and silence, do like me, buy a first prize fan.
Attention! This is my point of view to the use I wanted. If you are looking for high throughput without seeking silence, this is perfect!
Manufacturing side is a beautiful product, durable and well designed.