de rigueurde ri‧gueur /də riːˈɡɜː $ -ˈɡɜːr/ adjective [not before noun] 
considered to be necessary if you want to be accepted, fashionable etc – used humorously: 
the gleaming white teeth that are de rigueur for movie stars
considered to be necessary if you want to be accepted, fashionable etc – used humorously: the gleaming white teeth that are de rigueur for movie stars