Foreign Pension Income

Different pensions are treated differently - you need to know who the pension is from (ie. what type of pension it is) and what the pension says.  That being said, almost all foreign pensions are taxable unless they are some form of compensation for war acts, etc.  US Social Security is the only one I am aware of that uses the exempt portion box (15% is exempt if they started receiving it after 1995).  You are likely going to be correct if you report the pensions as taxable, but you should check the tax treatment in prior years to ensure you are being consistent.

My client receives a pension from Poland, where this pension is not subject to taxation. In which line should I put the amount of the pension received after conversion to $ CAN? Is it correct to use line foreign pensions exempt under a tax treaty, or maybe the line other foreign pension income. Please let me know. Thank you

If you have confirmed in the Treaty that it is not taxable in Canada (usually a military pension), then you record it on the exempt under a treaty.  If it is not taxable in Poland, but is in Canada, use the Other Pension line where it will be taxed here.