A taxpayer is allowed to overcontribute to their RRSP, without penalty, by up to $2,000. According to the Canada Revenue Agency, you must pay a tax of 1% per month on excess contributions beyond $2,000. To avoid this, you could withdraw the excess contribution. You’ll need to fill out Form T3012A, which informs the CRA that you accidentally overcontributed and requests approval to withdraw the excess amount.