It is difficult (my opinion) to ID Prussian blue paper from a scan. It needs to be certified with physical stamp in hand by an expertizer.
For what it is worth, it looks like the very common gray blue paper to me. Prussian blue should be noticeably darker if the stamp is not faded/worn. But my laptop monitor may not be reproducing your scan color accurately.
I forgot to mention, the stamp on the right should be the lilac blue paper. The paper color is very very light, which is why it appears white compared to the stamp at left. Put it next to a stamp on normal untinted/untoned paper, and you will notice the color.
I have not yet mastered the FRANCE SC#87. I easily confuse it with the SC#86a (Black on deep blue). When uncertain, I usually search the Philatelic Foundation's Certificates, which have several images. They list three of the SC#87 and also several they determined were not genuine, but SC#86a. I would have provided a link, but I'm still a newbie!