Long ago,Roman Polanski had warned us: beware of the neighbors, beware of those would be friends who ,little by little, work their way in to your intimate world : that was "Rosemary 's baby" and "le locataire " (the tenant ") ;paranoia had also been the subject of "repulsion" .
"D'après une histoire vraie" is psychological drama of the first order : Emmanuelle Seignier is as good as ever but the stand out is her co-star Eva Green : if looks could kill,her piercing green eyes certainly would ; always friendly ,but with something hard ,something threatening ;her motives remain obscure: a doppelganger , a lesbian attraction, something related to family past, a complete unknown in search of fame through an intermediary?
Green goes as far as to look like her victim, adopting her hairdo ( recalling sometimes Claude Chabrol's "les biches " ) .And the ending remains ambiguous ,you can interpret it according to your own sensitivity .
A weakness in the screenplay : the meeting with the librarian :the probability was close to zero! This is minor quibble though.