Richard Harwood KC, for Ms Shaman, had argued that Brockwell Park had "increasingly" been used for large commercial events in recent years, with "substantial" parts of the park being fenced off from the public during the events with damage caused to the ground.
"Due to inclement weather over the weekend of one of the commercial events, the park effectively became a mudbath," Mr Harwood added, referring to one event last year.
Matthew Reed KC, for Lambeth Council, said the "majority" of the park remained unfenced and available for the public to use during the events.
He also said that the council was able to lawfully decide how often the park was used for festivals and would grant special permission if needed.
However, Mr Justice Mould found in his ruling that Lambeth Council's planning officer had "erred in taking into account the mere prospect of planning permission being granted".
The Protect Brockwell Park group has previously said it is "not anti-festival" and supports "well-run, inclusive events".
The group said in a statement: "These large-scale, high-impact commercial festivals are damaging Brockwell Park's ecology, heritage and community value.
"The park is being overused and under-protected."
