Information about the birth of Augustin Jean can be found on the Isle of Jersey website which is Jerripedia. http://www.theislandwiki.org/?title=Jerripedia
Click on the words "Family Research" in the blue Main Subject section
Now in the "Church Registers" section click on "Church Records Database" then "Jerripedia family records database." There are probably several ways to get to the same place. Ultimately, you need to register and create a username and password.
The Jean family lived in St. Ouen parish. One option is to search for Family Name: Jean/ Given in St. Ouen parish. You will find in the index: Baptism: 9 Jan 1647/ Augustin Jean/ son/ Father: Edmond. If anyone is able to get an image of the original record please post and share.
Thanks, Karen Rasmussen firstname.lastname@example.org