There is one important difference when it comes to what rhetoric is suitable between France and Russia, I think. Russia has control over the narrative within it's land, about the media and limits free speech. If Russia doesn't follow up on it's threads, there are no internal consequences and externally, Russia might lose some credibility but still say an unpredictable danger. I think France has a lot more to loose when not following up on their threads / red lines. In terms of diplomacy with other countries, internally with the government appearing weak to its citizens and towards Russia too.