US studio Disney has defended itself against accusations it copied ideas from French author Franck Le Calvez in its hit film Finding Nemo.
The Disney cartoon has broken box office records
The author's publishing house has applied for an injunction to stop Disney distributing Nemo merchandise.
Mr Le Calvez registered Pierrot the Clown Fish in 1995 but Disney lawyers Nemo's likeness could not be considered a brand in its own right.
The judge will rule on the injunction request on 12 March.
Judge Louis-Marie Raingeard de la Bletiere was shown
extracts from the cartoon by Disney in a side room of the court chambers in central Paris.
He was also shown merchandise including cuddly toys, water pistols and colouring books submitted as evidence by both sides.
Finding Nemo is nominated for the Best Animated Feature Oscar
Lawyers for marine life enthusiast Mr Le Calvez said he
registered an outline of his clown fish character with the French authors' copyright association in 1995.
His illustration of Pierrot was registed as a trademark for Flaven Scene publishing house in February 2003.
Disney's lawyers said Walt Disney Productions and animation studio Pixar thought up the idea of Nemo and
registered their copyright as early as 2000.
"The trademark registered by Flaven Scene was a judicial
manoeuvre," said Thierry Mollet-Vieville, a lawyer for Disney.
Mr Le Calvez's book was first published in November 2002 and sold its
first print run of 3,000 copies.
But its second edition a year later sold hardly any copies as many bookshops did not want to stock it alongside Disney's Nemo books, published in France by Hachette.
"This is precisely the kind of case where our French
legislation protects us against globalisation," said
Marie-Catherine Brocherieux, one of Mr Le Calvez's lawyers.
"We have fought back because we are the ones who have been copied," she said.
A lawyer for Hachette said it could lose 700,000 euros (£470,000 or $880,000) from a ban on sales of Nemo books in France between now and the civil trial, which is due to begin in November.
The lawyer added that Flaven Scene had refused to put up guarantees it could repay that amount if it lost the case.
Finding Nemo, about a fish searching for his missing son, was the biggest US film at the box office in 2003 and has made $850m (£450m, 675 million euros) in ticket sales so far.