"The girls' newspaper."
Is this the only way of saying this? Would 'Les filles journal' or something similar ever be correct?
The possessive form <owner + apostrophe + possessed object> does not exist in French. the construction is always <article + possessed object + de + definite article + owner>.
- singular: le journal de la fille or le journal du garçon
- plural: le journal des filles or le journal des garçons
- please note that: -- "de le" is contracted in "du" -- "de-les" is contracted in des.