Does everyone know this already?

This morning I had a message from a telephone number starting 0035 - I didn't call it but was interested to know where it was from. According to Google it is fake number and that you shouldn't accept a call from them. Apparently you can use this legitimately if you are a write or TV producer and want to include a 'phone number in your work! Not quite sure how it works as part of scam but Google says on no account call it!!!