de minimis non curat lex

Wiktionary

1. law Literally, the law does not concern itself with trifles; expression of the rule that the law will not remedy an injury that is minimal.

GNU Webster's 1913

1. n. The law does not concern itself with trifles; -- a principle of law, that even if a technical violation of a law appears to exist according to the letter of the law, if the effect is too small to be of consequence, the violation of the law will not be considered as a sufficient cause of action, whether in civil or criminal proceedings.