who made this guitar?

[Sinier de Ridder]

Can somebody help us to understand who made this guitar, and where. We know another one in a private collection, excatly the same, and Kenneth Sparr knows another quiet similar, all unbranded, with no particular mark inside. The making reminds french lutherie as well spanish.  It has 6 courses, a bridge for knotted strings, a piece of canvas for the low brace as they did in France around 1770, the ribs are renforced as spanish luthiers did, and the neck/heel is in one block in a incredible style, never saw elsewhere! The purflings and the rose looks french, but not necessary.

Thanks in advance for some help!

Françoise