Please see Source: https://www.hodinkee.com/articles/bring-a-loupe-april-29-2016
The Type 20 is the proof that Breguet offers more than elegant dress watches with guilloche dials. Jack went all in with the modern edition here, but here you see a transitional version offered after the original 38 mm chosen by the French army in the 1950s. Indeed, Breguet released it after the luxury house Chaumet had taken control of the brand in 1970. On that occasion, the Type 20 got a larger 40 mm compressor case and a sleek black bezel. This version existed in both two and three-register layouts, with, respectively, the caliber Valjoux 235 and 725, both offering the flyback function that the original military contract stipulated. Note that this version never made it into the French Armed Forces, as its cost was judged excessive at the time. Finally, in 1995 Breguet released the current version of this chronograph, named Type XX instead of the original Type 20 borne out of the eponymous military specs. I wish this listing had a better picture, but nonetheless it seems the lume dot has disappeared from the bezel.
This Type 20 from the 1970s can be found for 13,000 Euros (or around $14,500) on a French forum here; it comes with the two last service invoices from Breguet, the last one dating only from a few months ago.