Arête de poisson (herringbone bond)

More often this herringbone pattern is referred to as opus spicatum. It is a stone bond in the shape of a herringbone, and found in carolingien (Carolingian) and préroman (Pre-Romanesque) buildings. This bond is abundantly present in the walls of the Saint-Laurent in Tournus.
There is some confusion about this term in French Wikipedia. They distinguish "appareil en épi de blé" = stone bond in the shape of ears of wheat (opus spicatum) and "arête de poisson". The difference is that in case of arête de poisson the joint between the herringbones forms a straight line, while in opus spicatum it follows a zigzag line.
The picture shows the only remainig bit of wall of the original Sainte-Marie in Bonnay.
See also opus spicatum.

Sainte-Marie - Bonnay