Preheat the oven to 200°F. Line a large baking sheet with parchment paper; set aside.
In a medium saucepan heat sugar, water and corn syrup stirring occasionally until sugar dissolves (3-4 minutes). Bring to a boil, and cook washing down the sides of the pan with a wet pastry brush to prevent crystals from forming, until it has reached an amber color (about 5 minutes).
Remove from heat, add in heavy cream. Return back to medium heat and stir in lavender, and fleur de sel.
Immediately drizzle caramel over popcorn, toss gently with a spatula until evenly coated.
Bake for 45 minutes. Stirring popcorn every 15 minutes so it is evenly baking.
Place a handful in a bowl and finish off with a sprinkle of fleur de sel.