Experimental data presented in our contribution provide a compelling evidence of generating Townsend-mechanism controlled breakdown in barrier discharge of coplanar geometry, which is known to have a highly non-uniform electric field that favors the streamer breakdown. When pure rare gases of helium or neon were used, a slow, wide front ionization avalanche is formed and propagates over both positive and negative electrode. Time resolved images of the avalanche propagation recorded by high speed ICCD camera and single photon counting are presented, correlated with the instantaneous discharge current.