I found that fabric in a stock dedicated to professionals, a kind of giant warehouse in which you can find a whole bunch of gems, ends of rolls (from 3 meters to about 20 meters) used by French fashion houses in previous seasons and left behind.
I was looking for the material of my dreams, hoping to find a fluffy tennis striped fabric. I immediately fell in love with this one, soft and a little elastic, which holds well! I wanted a tennis striped fabric because I was contemplating embroidering multicoloured threads between / on the stripes... Tada!