France have home advantage for the clash, and as if that wasn't enough, Johnson believes Bernard Laporte's side have enough quality to lift the World Cup later this year.
Johnson said: "On Saturday they (Wales) are going to come up against a very, very good side, a side capable of winning the World Cup.
"I don't say that lightly - I think France have more strength in depth than any other side in the world and they have a culture that enables them to play great rugby whilst mixing it too.
"That is why we have a massive task awaiting us in Paris. I know that we played well against Ireland and on another day we might have been talking of a victory rather than a narrow, last-gasp defeat. But let's face it, France in Paris in the springtime is an altogether different prospect."
Wales are hoping to avoid a first Six Nations whitewash and at the same time secure a record-breaking third successive victory in Paris.