en résidence à vs. en poste à

08:04 Apr 2, 2016 

would be "public administration", "civil service" or similar;

the fact that the whole of your ST is about tax evasion has no relevance for these two terms - they concern the status of civil servants pursuing the case.

15:55 Apr 1, 2016 

Thanks for comment re "presently" - for me it means at the moment which leaves one to assume that you were elsewhere before and will be afterwards (= currently). Will mull over.
I doubt that the Brigade d'Intervention Interrégionale is a private/residential address. This is why I thought that perhaps the "en résidence" meant that the person is being paid by this entity (residence sounds permanent to me) while being "presently" (temporarily) allocated to somewhere else. However, both you and BD Finch seem to feel that I've vice-versa-ed the interpretion so will bow to your joint opinion! Thanks very much

15:43 Apr 1, 2016 

Whilst I've seen "en poste" and en résidence" used with regard to professional locations and so related to work, I'm not sure how this fits with your labelled context of tax evasion. Does your context refer to professional locations or private residential locations?

15:37 Apr 1, 2016 

Just a note about the EN temr "presently". I never use this term as it always sounds a bit old-fashioned, rather twee, if you know what I mean? My brother uses it where I use the word "now". Thus, "presently residing at" does not necessarily imply a temorpary situation, but rather one that has changed. X used to live in one particular place and now lives/works elsewhere, in the place cited.

07:59 Apr 1, 2016 

I think that "en résidence" means where he/she physically is. I.e., he is an agent de la Direction..., but his office is located at the Brigade... "détaché..." means he temporarily works for that service, which doesn't necessarily mean he is physically present there. Administrative French is horrible - this is just my feeling, I am not sure. Normal logic cannot be always applied to governments...