First we are going to make sure our Swatch variants are correctly selected for our translated variant names.
We can go to theme customization -> theme settings -> product -> adding "Couleur" to the Variant options for swatches. ( We are adding "Couleur" in this case because we are configuring for the French language)
Now the Swatches are displaying on our translated page, but the colors are blank.
Lets inspect the Swatch (In the Google Chrome inspect tool) and see what colors are being chosen to display
In the above images, we are inspecting the first swatch bubble.
We can see the background-color, and the background-image that is being used to display the colors in the swatch.
The issue is the provided url for the background-image does not exist, so the Color is blank.
Also, the background-color value being BleuNavy, also does not exist, so the Color is blank.
In order to resolve the issue, the background-color would need a valid color value, or the background-image url would need to be an existing image.
If your swatch is broken on your stores Default language pages, then please reach out to your Theme Developers as it is a Theme issue.
However, if the swatch is working on your Default language pages, but only broken on translated pages, please reach out to firstname.lastname@example.org where we can help you further.