There are of course, two things you're looking for in a biography. One - the story of the protagonist, and two, some goddamn literary merit to the writer. Rivoire is a prolific sports writer (having written too many of these biographies on everyone in the field) apparently, and that only makes me completely suspicious of him. I'd prefer my biography to be written by someone who has a personal story concerning why they chose their subject, etc.
In the absence of all that, I'd at least expect a little flair for writing, which, I'm extremely sorry to say, is extremely lacking in Rivoire. It's a book about a man I'm increasingly fascinated by, but also a book that hardly features any quotes or anecdotes by him. I'm new to football, so parts of the history seemed too hard for me to comprehend in one go, all these names being thrown around.
It's an okay read, I don't think anyone will be wowed by the book, I'd rather wait for Wenger's biography. At best, Arsene Wenger: The Biography is like an ill-researched private detective's sly, behind the scenes reportage; so you might just be better off reading his Wiki page.