Public displays of homosexuality will be banned in St Petersburg.
Governor Georgy Poltavchenko signed the law. It will mean fines for people who promote "public actions aimed at propaganda of sodomy, lesbianism, bisexuality, and transgenderism among minors".
The fines range from 5,000 rubles to 500,000.
St Petersburgs politicans claim that The heavy sanctions aim to protect children from homosexual influences.
Vitaly Milonov authorised the controversial law.
"We see how the world is changing. We see blasphemously, how the standards are being changed, and how the traditional values are vanishing - values which our society and all Europe were built.
We don't want for this process to happen in our country.
We see how children in some countries are made to sing songs 'I have two dads' and others have to listen to it. We think that it's not right".
"Naturally, if the people who belong to those non-traditional groups criticise this law.
What can I say to this? The law was passed to protect children, but in no way against homosexuals.
And this is the point. So if anyone criticises it, then it means that they are worried and need to influence the children."
According to Amnesty International and Human Rights Watch the move will increase discrimination among gay people.
Russia decriminalised homosexuality nearly 20 years ago- but this law is set to hit the statute books on the 17th of March.