Federal Act
on the Amendment of the Swiss Civil Code
(Part Five: The Code of Obligations)

¹ Where the pay­ment was fixed in ad­vance as an ex­act amount, the con­tract­or is ob­liged to pro­duce the work for the agreed amount and may not charge more even if the work en­tailed more la­bour or great­er ex­pense than pre­dicted.

² However, where pro­duc­tion of the work was pre­ven­ted or ser­i­ously hindered by ex­traordin­ary cir­cum­stances that were un­fore­see­able or ex­cluded ac­cord­ing to the con­di­tions as­sumed by both parties, the court may at its dis­cre­tion au­thor­ise an in­crease in the price or the ter­min­a­tion of the con­tract.

³ The cus­tom­er must pay the full price even where the work has en­tailed less la­bour than pre­dicted.