Question juridique clé
Whether the respondent had to mitigate its damage by invoking prescription and informing the appellant of the tax proceedings under Art. 44 CO.
Solution extraite
The complaint failed because the alleged facts supporting a mitigation defense were not established in the cantonal judgment and had not been properly pleaded below.
Motifs extraits
In reform proceedings the Federal Court is bound by the facts found below. New factual allegations, including prescription, waiver of prescription, or lack of information, cannot be added where they were not timely pleaded under the cantonal debate principle.