We use the phrase "on par" for comparison of two things that are the same or equal.
Example: The specifications of these two cars appear to be on par.
"Par" can be used in the financial market. It means the current market value of a share or a bond is the same as its face value. We can say that the market value of shares of ABC company is "at par", "above par" or "below par".
Hope this helps you.