Hi El,
Would you mind providing your admin login too?
For the meantime, please check this http://tools.pingdom.com/fpt/#!/dQQoPG/http://techvslife.fr/
The blue color is when browser request connection to your server. The green is when your server replied the processed request to the browser. The yellow is the wait time where processing took place (wordpress, theme, plugins etc.), processing just take about 200ms. But connecting and receiving from your server took about 4000(4seconds).
4 seconds is still not that slow, which means your site is already loaded at the browser. But there is something that keeps your sites from rendering in instant. It could be 3rd party plugins that uses css and javascript that taking long to process to your browser. We need to find what module of jetpack that causes this, though I can’t promise a fix. Your last option is to disable jetpack as a whole.
Thanks!