For example in C-528/15 (
http://curia.europa.eu/juris/document/document.jsf?text=&doc...)
"As regards the wording of Article 2(n) of the Dublin III Regulation, a purely textual analysis of the notion of ‘defined by law’ cannot determine whether case-law or a consistent administrative practice are capable of coming within that concept. In the different language versions of that regulation, the term equivalent to the term ‘loi (legislation)’ has a different scope. Thus, the wording used, for example, in the English-, Polish- and Slovak-language versions is similar to the concept of ‘droit (law in the general sense’), which can have a wider scope than ‘loi (legislation)’. Certain other versions, for example, the Bulgarian-, Spanish-, Czech-, German- and French-language versions, have a more restrictive scope.
32 Where the various language versions differ, the scope of the provision in question cannot be determined on the basis of an interpretation which is exclusively textual, but must be interpreted by reference to the purpose and general scheme of the rules of which it forms part (judgment of 26 May 2016, Envirotec Denmark, C‑550/14, EU:C:2016:354, paragraph 28 and the case-law cited)."
As already mentioned this is often just one part of a bigger ruling and the translations are often good enough so that it's not necessary to dissect the whole text like this.
By the way: I think it's an interesting challenge to translate the Treaties (and regulations etc). You don't want to have too much divergence between the different language versions but sometimes it can be very difficult to translate something exactly without using a lot of words.
One tactic that is used in European law in this regard is to start the regulation with a preamble "definition" section (similar to writing a program) where you define all the important words/phrases.