My impression is that legal language and terminology are more orderly than the terms of other branches of knowledge, particularly medicine, the most ancient and the most chaotic. Lawyers often have to define their terms before they use them, especially in the case of contracts. (Lawyers are linguists; doctors and engineers are not.)
Pitfalls are innumerable. An entrepreneur (F) may be an entrepreneur, but he's more likely to be a 'contractor'. A term such as association (F) has many legal meanings when it has collocates such as momentanée (joint venture, in Belgium), en participation (partnerships of various kinds), syndicale (property owners' syndicate), de malfaiteurs ('criminal conspiracy'), whilst 'association' (E) has technical meanings in psychology, chemistry and ecology, sometimes unhelpfully obscured by a lack of collocates. But even in legal texts, when terms such as association, définitif (definitive, not final), société, structure etc are used non-technically, as ordinary language, and without collocates (note structure d'accueil, 'reception facilities') they should be translated literally.
A semi-legal collocation may have several meanings: tomber dans le domaine public: 'come out of copyright', 'become government property', 'fall within the public domain' (no longer secret).
The essence of legal language is not spoken but written language, not 'how would you say it?' or 'would you hear a lawyer say that? but 'would you see that in a legal document?' Pétrole may be called 'oil' or 'crude', but in a legal or scientific document it is 'petroleum'.
Many of the 'targeteer's' normal ideas of style go by the board in legal translation. An annexe (F) is an 'annex' (E), not an 'appendix'; a juxtaposition (F) is a 'juxtaposition', not an 'association'. Such correspondences may not apply in the case of collocations. But normally, literal translation comes into its own. In fact, there are little differences of meaning in these examples, but clients will frequently try to exaggerate them. (I use the coinages 'targeteer' for a target language-oriented translator, 'sourcerer' for a source-language oriented translator. Both terms are 'translations' of Ladmiral's ciblistes and sourciers respectively.)
For the lay person, legal language is a minefield. Who would think that à la diligence du ministre is not 'at the insistence' but 'at the request' or 'on the initiative of the minister'?
Peter Newmark (1993) Paragraphs on Translation, Clevedon: Multilingual Matters, pp. 16-17.