Indeed, you can use version 2.5 of the API which is free (no credit card) and offers the same functionality.
http://api.openweathermap.org/data/2.5/weather?lat=43.267093\u0026lon=-0.421642\u0026lang=fr\u0026units=metric\u0026cnt=1\u0026appid=XXX
Should I update the tutorial with both options or only this one? But wasn’t there some talk that you could no longer get a key for this version?