If it’s anything like in the linked video (https://www.youtube.com/watch?v=v1kK-EPxtwk), it might be called larmes de chocolat.

I think that we’ll have to speak simply of “(fines) feuilles de/en chocolat” (ref1, ref2, ref3).

Copeaux can be used for your situation if each piece were irregular in size, as copeaux size and look can vary from any persons opinions, but in any case each pieces would be differents.

Like in your image a copeaux is small for you, but for me a copeaux is like that in size; wood copeaux in the picture, but it can be bigger as you can see.

If big like a page and small in width, LPH’s answer would be a better fit.

Complément fait après ma réponse initiale

Au départ pour moi des volutes de chocolat c’étaient des sortes de triangles plus ou moins grands, assez proches des pétales. Voir sur ce blog consacré aux diverses décorations en chocolat la fabrication de volutes. Et une fois sur le gâteau ça donne ceci.

Mais il semblerait que les professionnels appellent volutes des constructions plus volumineuses qui peuvent prendre des formes et des tailles différentes, le point commun étant la forme courbe ou arrondie et d’après les divers exemples que j’ai vus le mot s’appliquerait bien à ce qui est décrit dans la question.

Du plus simple, au plus élaboré, jusqu’à la tarte caramel beurre salé « sublimé par des volutes de chocolat noir » de ce pâtissier qui montre divers exemples de réalisations avec des volutes.

Three words words could fit your description, copeaux, tuiles and pétales. You are excluding copeaux for what – in my opinion – is the wrong reason: size. Copeaux de chocolat can be as big as you wish and physical constraints allow. Proper copeaux are made from melted chocolate that is spread onto the worktop and grated with a spatula (or knife blade, which I think is more difficult) when starting to thicken but still warm so that the pieces will roll onto themselves. The longer the spatula (or knife blade) the longer the copeaux.

This picture shows what I consider to be medium size copeaux decorating the top of a cake. And here is a recipe.

Whatever the size, copeaux roll onto themselves. You can make all sorts of decorations with chocolate copeaux including the petals of a flower.

If the decorations you saw did not roll onto themselves then I would not call them copeaux. They would be more like tuiles en chocolat. Tuiles en chocolat are also made from melted chocolate that is shaped while still warm. You pour blobs of melted chocolate onto a non stick paper sheet on your worktop, spread the blobs as thin as you wish, or can, and then slightly roll the sheet and keep it into place until the chocolate has cooled. The bigger the blobs, the bigger the tuile (and the more difficult it is to make).
Here’s a recipe and what it looks like.

A pétale de chocolat is a tuile that has been shaped as a petal, maybe not so regularly round, but the making process is similar.

Here’s a video (0:41) of a cake being decorated with pétales de chocolat. Small ones, I admit, making big ones might be a challenge to the layman.

^{If anyone thinks this should be on Seasoned Advice, then I’ll gladly delete my answer. I just felt I had to expand a little as there seems to be a confusion between chocolat rapé (OP’s picture, or here) and copeaux de chocolat.}