Well , yes I know about the Japanese fm band. But laymen in my region do not posses a scannar or an expensive piece of communication reciever. So, hopefully none but me will be able to listen to it. Maybe government guys will monitor me but I ain't gonna transmit anything illegal and the power of the transmitter will be in milliwatt range.
The receivers which could pick you up would be 40 year old Japanese FM radios, which could well be lying around in many houses.
This doesn't address the possibility of image interference in normal FM receivers.
Old scanners would not be very expensive, so there may quite a few more around than you imagine.
What do you intend to do with the thing, talk to yourself?
I do hope you don't envisage using it as a clandestine "bug".
That opens a whole other "can of worms", as you could get arrested under city or state laws, as well as possibly being sued.
"What was I thinking of?"-----of course, you wouldn't do that.
If you were in Oz, that band would be the old CH2 TV Band.
As far as I know, it is used by "land mobile" here.
I'm not sure about the allocation in your country, but don't be surprised if you are crunched into the noise by a big, beastly FM comms signal.