It is understood the incidents occurred between Tuesday 10th and Thursday 12th of January.
The seven stickers, which included swastikas, were found at Piccadilly Circus and Covent Garden stations.
The stickers were quickly removed.
Investigating officer Ben Hurley from British Transport Police, said: “There is no place for intolerance and racism in our society and we take a firm stance against anyone who carries out these offences.
“All instances of hate crime are taken extremely seriously and we would actively encourage anyone who has spotted these stickers on public transport to contact us.
“Our enquiries are ongoing and I am hopeful that someone will recognise the man in the CCTV images.”
Anyone with any information is asked to send a text to 61016.
You can also call 0800 40 50 40 quoting reference 174 of 07/02/2017. Alternatively, contact Crimestoppers anonymously on 0800 555 111.