Restaurants have been preparing for months to implement a rule that comes into force on January 1, which for many has upended business models based on single-use packaging and utensils, both for eating in and for take-out."It's an emblematic measure that if properly implemented will make a very concrete difference for people -- it definitely goes in the right direction," said Moira Tourneur of non-profit Zero Waste France.At a McDonald's in the Paris suburb of Levallois-Perret, manager Maria Varela said they needed to hire an additional dishwasher and more hosts to explain that plates, knives and forks must now be separated from trash."At first it was very complicated, both at the counter and with table service," she said, noting that the kitchen had to be remodelled to cope with the new requirements.Several including Surfrider, Zero Waste France and No Plastic in My Sea have urged clients to "sanction the chains that don't respect the law" by taking their business elsewhere."