It is really hard to tell exactly how much weight would correspond to the free weights when compared to smith's machine. First of all, all of them are different, and as @muskate has said, they might have different resistance, which would affect the weight as well. Secondly, it would be hard for you to repeat the exact same movements with free weights.
So if you want to do something similar, just use the weights you feel comfortable with - don't try to repeat the weights you use with the smith machine. Use the weights that fit you best, and gradually increase them.