Tahoe

I know I should feel bad, but there's something about reading the words lake and fire in the same headline that reminded me of this one:

• un lac = a lake
• un feu = a fire. In the case of wildfires, arson or accidental fires, we use un incendie

which leads me to the expression:
il n'y a pas le feu! (y a pas le feu! for short) or y a pas le feu au lac! = no need to rush, there's no emergency (literally there's no fire and the lake is not on fire, respectively)

While it's pretty clear why the absence of a fire means there is no need to rush, the mischievous addition of the lake is (allegedly) a reference to the Swiss - and their lake Léman - whom in France have the reputation of being slow. That expression is therefore better used with a forced Swiss accent!