I would say it depends on what your players want to play.
Do they want more action/adventure oriented play? Then just give a summary of the exchange. This playertype would easily get bored, if you tried to play out a whole conversation. Next thing is that this type of player would like to be the hero, so they want to be part of the conversation (not necessarily but mostly) and not just sitting by.
If, on the other hand, your players are more story/character oriented then play it out. It's a unique opportunity to give characters flavour through choice of words, agitation in speech and voice acting. It needn't to be superior voice acting, but even a french accent can enhance every atmosphere.
If you're planning to go through a whole conversation with your NPCs, it's possible to give hints on how to solve a problem. The players won't get every single one of them, but they needn't to since it should make their life a bit easier and not be the method to solve their problems.
To achieve this you should distinguish your NPCs. Try different pitches for every NPC, different accents, different speech styles so every NPC could be recognized just by talking. If you get the feeling that your players are confused which NPC said what, just throw a bit of "Jim said" in and let it be part of a narrative.
But as stated above the whole procedure depends on the playstyle of you and your players.