Would it be okay to paint mini paper lanterns with acrylic paint? Is it flammable?

I bought these adorable little paper lantern lights for my new apartment. Only problem is that they are a bit plain. I was going to paint different flowers on each little lamp. I paint a lot, but I only have acrylics right now. I hear you have to be really careful with lanterns catching on fire. Would the acrylic paint on the outside catch fire? Is it flammable or safe enough?