For its time, le Bijou is a nicely made, straightforward and lightweight single pulley derailleur.
The instruction sheet says that if the largest sprocket has more than 22 teeth, you should move the slider rods into the lower pair of holes in the main arm. Many decades later, Huret used a similar idea on their Huret Challenger (2440) and its later variants.
Another small feature that caught my eye is the slight curve in the black plate mounted on the inside end of the slider rods. This curve is a 'spoke protector' and again pre-figures a multitude of later designs that had cuved portions of their inner pulley cage plates - Shimano, in particular, were/are keen on this feature.
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