Peter wrote:
However, it doesn’t look as if anybody knows, or has come across that option to submit aircraft docs in advance.IF such a system exists, it may be something operated by French airport police, but with no access to Joe Public.
According to https://www.douane.gouv.fr/demarche/vous-souhaitez-obtenir-une-carte-de-libre-circulation-des-marchandises, you can do that at any douane office or entry point into the country, presenting the goods (the aircraft) along with the proof of VAT payment (e.g. an invoice) / import processing (copy of the import declaration?). You get a card that you can use to get out further controls. In case of change of ownership, the new owner can show the card of the old owner to get his own card.
Since you will have difficulties to bring the aircraft to “any” douane office, I suggest you do it at a douane office situated at an airport, or by prior arrangement with the douane office in charge of entry/exit checks at that airport (cf AIP).
List of Douane offices: https://www.google.com/maps/d/viewer?mid=15NzqQ3i4s8r4CPiMMT8ZPLD4iMA&ll=-3.81666561775622e-14%2C-69.13444850000002&z=1
Bonus points if you do it in St-Pierre-et-Miquelon, Mayotte, La Réunion, Guadeloupe or Martinique ;-) Or maybe even French Polynesia?
Maybe you are refrring to “Quitus Fiscal” to prove VAT on private vehicles (e.g. car, boat and aircraft) in France?
The process is painful: the only form available is for cars not for private boats or aircraft, you have to be French resident as it’s only done in your nearby service des impôts des entreprises du centre des finances publiques
Quitus Fiscal is useful if you want to put your aircraft on F-reg with private title on DGAC register 
I doubt it’s connected in any way to the ‘service’ or ‘hit-list’ in OP question…
