Enter the information from your RL1 box 211.  This will ensure that the amount is treated as "previous employment", rather than "regular employment" income.

See the link below from RQ to learn more:

201 – DEDUCTION FOR WORKERS

https://www.revenuquebec.ca/en/citizens/income-tax-return/completing-your-income-tax-return/completi...

Next year, you may  want to contact your former employer and ensure they enter in that amount correctly on a Tslip for tax purposes.