Not a subject I know much about - but according to this link I found it seems to be more than set design and may mean something like theatre layout e.g. in the round etc.

A bit more context might be helpful - is this in a theatre, open-air?

le cube

..lab[au] + [ Res Publica ] invited with their interactive scenic device ... exercice pour un nouveau millénaire (dispositif scénique interactif, ...
http://www.lab-au.com/files/doc/cube.htm

[XLS]
English
File Format: Microsoft Excel
3218, Scenic device. 3219, schizencephaly. 3220, Schizophrenia ... 1015, Dispositif scénique. 1016, Dispositifs médicaux. 1017, Dissection anatomique ...
http://www.editionsmf.com/getkeywordlist.jsp

Shania Boards - Montreal Concert!
Son dispositif scénique et sa mise en scène étaient du même ordre: ... Her scenic device and her present were same order: imposing and tape-à-l'oeil. ...
http://www.shaniafans.com/mb/showthread.php?t=13941&page=2&p...

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English context:

The company xxxxxx is concerned with the stage as space of representation. Their performances precede neither from a body-oriented standpoint (dance) nor a dramatic narrative oriented one (theatre). Their investigations of stage question the construction and arrangement of space, the structure of representation and the relationship of stage and public. Their centres of interest are formalized in “scenic devices”.

The term of the "scenic device" is defined in opposition to concepts of representation in terms of a metaphorical translation of reality. The creations of res publica are scenic devices where the theatre as place of performance as such, is analyzed by the transformation of its setting. The performance is understood here in the sense of a cultural practice and thus socially, historically and technologically determined. In this perspective, the devices both deconstruct and reconstruct representation. The scenic devices operate by the categories of space, interpretation, public, time, and action.

http://www.lab-au.com/files/doc/co-sign.htm

"the proposition in terms of the scene settings (how the evaluators planned to fund the scene settings or mechanism) was clear and strong."

scénique < scène < stage

dispositif < lay-out

If that's all the context you've got it's a tricky one but my money would be on this solution (if I were a betting man).

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Note added at 11 hrs (2007-01-23 08:21:17 GMT)
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http://www.civilization.ca/educat/mentor/ssf/msdfra.html

*DISPOSITIFS SCÉNIQUES*

Le dispositif scénique est ***l'ensemble des moyens utilisés pour mettre en scène*** des marionnettes.

http://209.85.135.104/search?q=cache:PuS0tkj-A0cJ:www.syndea...

Le(la) décorateur(trice) maquettiste:
sur les indications du metteur en scène, conçoit *les maquettes des décors* (ou du *dispositif scénique*), et éventuellement des costumes, accessoires, masques, etc., nécessaires à la présentation d'un spectacle et, à ce titre, il(elle) a qualité d'auteur.

Le scénographe:
est un(e) collaborateur(trice) direct(e) du metteur en scène. Il (elle) est responsable de ***la conception et de la création du *dispositif scénique***, surveille son exécution et peut éventuellement y collaborer.

Theatrical devices

Staging equipment

http://www.google.fr/search?hl=fr&q="dispositif scénique"&me...

Plenty of hits, from which you should be able to figure it out.

Play safe and use something general -- it's obvious from the above what the general idea is.