Help Identifying Antique French Undergarment Please!

[Coran Beck]

Hello fabulous fashion guild members! I have several pairs of these knit, hand-sewn undies that I sourced from a farmhouse in the French Alpes. As I've not ever seen anything like these, I am hoping someone may be able to tell me how old they are, please? (I presume early 20th century - like 1910ish?) Thank you in advance!
P.S. yes, I do also have the soft corset/bodice that these button on to!)

 

[dollsntrolls]

What is the fabric? They seem skimpy, on the bottom part, for 1910s. I wonder if they are part of the underpinnings for an athletic uniform? Very cool. Can you show the whole piece, all put together?

 

[Jonathan]

It looks like it was something and then altered, at home, into something else. The button holes suggest it was attached to something else at the waistband... I would consider it an anomaly. I can't even quite understand how it is worn - I would need to handle it.