It would be a dangerous and costly mistake for anyone thinking of buying any tandem frame from a French mass-producer such as Lejeune, Peugeot, Motobecane, Gitane, Gottfried etc to assume that the frame had been built by the reputed Lyon-based builder, FOLLIS. That would be far from the truth.
FOLLIS built some of the finest hand-built French constructeur tandems of recent years..they are beautifully designed, crafted and finished. The mass-production tandems were generally built in-house by the manufacturers although some brands such as Lejeune might actually have bought theirs in from one of the large specialist frame-builders/suppliers to the trade such as Valdenaire.
While FOLLIS ( Mr Chollet) never exercised his torch on any lesser tubing than Reynolds, these mass-produced frames relied heavily on the maker's own brand high grade carbon steels..was Motobecane's called 2040 or something like that? Peugeot's frames were constructed by the firm's patent internal brazing system which involved slugs of brazing alloy being located inside the tubular structure near the mitred joints. The externally applied heat melted the alloy and drew it through the joints. I have, over the years sold all these brands and cannot recall a single one...certainly not in the UK, that had forged drop-outs at the rear.
Having said all that...I reckon that they were excellent value for money and many have served their purchasers really well over the years. However, on the UK market while all the brands were popular, they never matched up to the quality of the mass-market offerings of Holdsworth, Claud Butler and....of course (Barrie..are you reading this?) DAWES.