Escalation missions are objective specific missions that increase in difficulty with each success. They start out with a single main objective. After completion, you move onto stage 2, which adds either a 2nd objective, or a complication that makes completing the objectives more challenging. This process continues for stages 3, 4, and 5, which is the final stage. Completing the objectives of stage 5 unlocks the trophy upon the mission score screen.
Although there was only one escalation mission available for Paris when the DLC was first released, there are now 10 different options. Completing all 5 stages of any escalation mission located in Paris will award this trophy. Some missions are noticeably more difficult than others, but when you know where to go, and when, this trophy becomes almost trivial.
The mission I found the simplest, and definitely the quickest, was 'The Marsden Isotopy'. After learning the path, you can complete each stage in just over 2 minutes, and counting the loading times between stages, thus trophy should only take 15 minutes total. Although I usually make written guides, following this video guide should prove very straightforward and simple!
The only selections required in mission planning are to bring the Fiber Wire, and to select your starting location as Undercover in AV Center.
http://m.youtube.com/watch?v=g8xjGdqWuDAHappy Hunting!