Going yarn shopping in Paris is easy but you need a little preparation with maps. The city can be confusing to foreigners.
I included a map with the "arrondissements" or districts. There are 20 in Paris. It starts with the 1st one in the center of the city and continue in a shape of a snail.
You can find the district number on the upper part of the street signs at each corner.
If you get lost, just look at the sign and you will immediately know where you are.