For the European market, there are quite a few battery operated or battery free (but not mains powered) devices. Is that something you might be interested in? You would leave the original switch in place and either put a box cover over it or a baby lock on it and leave the current active to the bulbs. then use the battery operated device to actually control the lights.
You can see some of the possibilities in the buttons FAQ. The description should say whether it is mains powered or battery powered. The FAQ is intended to only have one or two posts per device and to link to a discussion thread about the device. If you have any follow-up questions, please put them in that discussion thread or come back here and ask so that the FAQ remains usable for others. Some of them look just like regular switches.