français term (edited): (en) régie

Not quite sure why you've included the 'en' — it might have helped to give us the actual source text in which it appears.

'control room' is the only general-purpose word I've found that covers pretty much all eventualities — though do note that different sectors of the industry also have more 'jargon' terms for it, for example, in UK broadcasting, it has traditionally been referred to as 'the gallery' (almost always with the definite article!)

Note that sometimes it may be '(sound/lighting/etc.) control position OR desk' — this applies when it is open and located in the actual auditorium, as is often the case at pop concerts etc. — and of course, it's often a great deal more technically complex than the mere term 'desk' might suggest!

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Note added at 27 mins (2009-07-20 15:42:10 GMT)
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I would say definitely not 'A/V room' — that kind of under-sells it, and could just be a glorified cupbaord where projectors etc. are kept. Generally, A/V or A-V is a term once popular in education and training, but little used in the professional media industries.

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Note added at 44 mins (2009-07-20 15:59:12 GMT)
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In the light of your added context, then I'd definitely say 'in the control room' — if the text were intended for an uninformed lay audience, you might want to add 'technical control room', but that could sound naïvely quaint to anyone with technical knowledge!