Full bleed means that you can print onto paper larger than Ledger or in your case A3, then cut away the extra paper with the margins. In the US full bleed specifically means 12" x 18" paper, that can be cut down to 11" x 17". I'm not sure how that applies in the metric scheme of things for A3.

Regardless, every printed page has margin voids. If you want print to the edge, you'll have to use larger paper and cut off the excess. Any image that is printed right to the edge will try to wrap onto the fuser rollers. It may accordion into the claws, or it might wrap. =^..^=