Why always so negative and in oposition?
Everybody can see a rhombus and it looks like the mentioned mark. Better photos are for some people not possible - so there is much room for guessing.
The import mark from Riga is clear and correct, There are many examples that via Riga imported silver has this misterious mark. The blurry, obnoxious photo show something in a rhombus. What is not clear - but it seems likely that it could be the known mark of an unknown maker some of us have often seen on. French silver very seldom has model/design numbers.
We can speculate with some suspicion until we perhaps get meaningful photos. Only than it is time to make a clear decision.
Just to remember what everybody can see:
The bear in a rhombus

something like a rhombus with unclear figure and the importmark from Riga in a photo of offensive quality
