  The self-similar cluster fluctuations of directed bond percolation at the
percolation threshold are studied using techniques borrowed from
inter\-mit\-ten\-cy-related analysis in multi-particle production. Numerical
simulations based on the factorial moments for large $1+1$-dimensional lattices
allow to handle statistical and boundary effects and show the existence of weak
but definite intermittency patterns. The extracted fractal dimensions are in
agreement with scaling arguments leading to a new relation linking the
intermittency indices to the critical exponents and the fractal dimension of
directed percolation clusters.
