I agree with Phil that this reference should be reproduced as it is in the English translation. However, the answer to your question is that c. stands for
considérant. Here is ATF 98 II 325; the Considérants are quite near the beginning:
http://relevancy.bger.ch/php/clir/http/index.php?lang=fr&zoo...In the United States these are called conclusions of law, as opposed to findings of fact. In the UK they are sometimes called rulings of law. Another word sometimes used is "grounds".
In other contexts, such as directives, they are called recitals.