I imagine the taking if Paris like one of the pages of The Playbook by Barney Stinson:
First: Take the cross from your dead priest friend, say sorry to him
Second: Shave your head completely, like...a monk
Third: Go to Paris and try to conquer it with all your forces...meanwhile some of your enemy in your side could possibly die
Fourth: When nothing seems to work, you'll end badly wounded...everybody in paris would be happy, but actually you're fine
Fifth: Let everybody know that before you die you want to became christian and be buried with honor in paris
Sixth: You die and the parisienns will accept your coffin and your honor parade inside the city
Seventh: Once in the city, jump out of the coffin, slay them all, now the city is yours!