Bring change if you aren't hitting your hotel for a while in Paris and other metropolitan European cities. Using the sansinette is going to cost you (usually less than $1, or equivalent). Also, bring your cell phone -- in Finland you must send a text message to the National Road Service to remotely open a pay toilet [source: Cellular-News].
These pay toilets are usually clean, most being sanitized automatically as soon as the door shuts upon each exit. Many are on timers, so you shouldn't loiter or the door will unlock on you and cleanser sprays will emit from vents in the walls. Also don't try to toilet hop -- trying to save yourself a few extra coins by jumping into a pay stall that's just been vacated will only end in tears -- probably literally, since you'll get doused with disinfectant at the same time as la toilette.
The toilets themselves tend to be Western in style, though often the water tank is above your head or even built into the wall behind you. Further, the flusher can be difficult to locate, often nearer to the sink than the commode, so look around. Many of these toilets are descended from models where the entire toilet flipped back into the wall upon commencing of the cleaning cycle and then hosed out automatically before being flipped back in. Very James Bond, though it's hard to picture 007 on the can.