i had a similar clicking on my french bike, and this was after servicing the pedals (ATOM) and BB (TA). turns out i hadn't tightened the pedal bearings enough to make them "happy", even though there was no free play. another 1/16th of a turn of the cone and all was well.

i've also gotten rhythmic creaks and clicks from BBs and saddles. for saddles, i first make sure the seat rail clamp is tight, then i apply light oil to the saddle frame, especially around the tensioner. for BBs, they usually just need servicing and adjusting, unless you have actual pitting in the bearing races.