Slowing down the website

I was wondering what was slowing down my wordpress and I found that my page speed went from 48 to 73 by deactivating the plugin.
I need this plugin but I can’t have a 2 seconds load time for each page.
Do you know where I should look at ?
http://galeriepolaris.fr
Thanks