Thomas Owen was out on licence when he met a young woman with the child, but he failed to mention he was on the sex offender register. Under the terms, he must report to police that he was staying at a house where a youngster was present.
The 30-year-old met the woman last month and stayed at her home for several consecutive nights, prosecutor Emily Hassell told Leeds Crown Court.
He eventually confessed to her that he was on the offender register. He was jailed for nine years in 2019 for sexual activity with a child, and was only released on licence in August. He is on the register and is subject to sexual harm prevention order (SHPO) for life.
The concerned woman reported Owen's overnight stays, and said although she often left the baby with Owen while she made drinks or went to the toilet, he was never left alone with the child for any length of time. There was no suggestion Owen, of Park Green, Normanton, had planned or attempted to abuse the child.
Owen was arrested on September 25 and claimed he was confused about the terms of the register.
He admitted a breach of the terms. Mitigating, Harry Crowson said Owen had simply "fallen foul of a misunderstanding".
But this was rejected by Judge Ray Singh, who jailed him for six months. He said: "I do not accept there was misunderstanding, this was a deliberate and persistent breach."