When could it be considered that someone is totally fluent in a foreign language?

Some people say that a high level in a language is only achieved once you can talk/understand no matter what kind of conversation. There are others who believe it happens when you can express yourself using idioms, irony or double meaning expressions. What do you think about it?

Internship in a law firm Dear John, Last year I did a 3-month internship in one of the most important law firms in the country. After this enriching experience I now feel much more confident in order to face common legal issues. Regarding the work at the office, I used to have a close-knit with my colleagues as many of the cases we had to deal with were interdisciplinary. On an almost daily basis I had to make deep comparative law researches as well as contact several judges all around Europe. This also allowed me to practice different languages which is something I personally find quite valuable. For all of these reasons I can only encourage you to do the same and apply for a vacant in a big law firm. I know some people could think that this is a stuck behind a desk work, sometimes overloaded and underpaid, however this opinion is nothing further from the truth. I can only tell you that If I had known that this was so interesting I would have applied for this internship before. Regards, Antonio