There are a couple things you could do.
1: Add a layer specifically for particle effects. It would have to be above the background layer and below the character layer. Then when you create a particle object, make sure it is created on this layer.
2: After spawning a particle object, send it behind the character by using the "Move to Object" action. This allows you to set if it is in front or behind the character.
In my opinion, the first option is the better one. It is more extensible if you set specific layers for different objects. It also makes it easier when testing.