The ad shows clips of Hollande traveling to and interacting with residents of Parisian suburbs. It is believed that Hollande's clip is designed to underscore incumbent Nicolas Sarkozy's tumultuous relationship with these diverse, often impoverished areas (in 2005 as interior minister, he said he'd clean out the suburbs with a power hose).
After the first round of voting on Sunday, Hollande leads Sarkozy. Since neither candidate took a majority of votes, a second round will be held in two weeks.
As Slate also notes, the video has made possible a superb pun: The town Hollande visits is Creil, which is pronounced "cray." You can fill in the rest.