I think I was expecting more from this book, given its popularity on GoodReads. For one thing it is written in a style suited to quite young children, yet the content is definitely too promiscuous for that age group. For another, the translation doesn't really work; it came across as if the main characters were speaking to French people in English. And I also wonder why the two boys, Kleber and Barnaby Maluri are chosen to be of Arabic descent, an extra complication that is never really dealt with.
Barnaby, known (rather insultingly) as Simple, is 21, but has a mental age of 3 1/2. He's been institutionalised for many years, but is very unhappy there, so his younger (17) brother has decided to remove him and find a place for them both in Paris.
They eventually find a shared house, with four students, and most of the story covers the interaction between themselves and this group.
The characterisations were good and the way the students learned life-lessons from Simple, and vise versa, kept my attention. My favourite character was the talking rabbit, Mr Babbit, Simple's life companion and soft toy, who voices many of Simple's worries and frustrations.
A quick, easy read, but not a book I would particularly recommend, unfortunately.