codified in Germany as ยง477 BGB (other countries accordingly)
edit:
Article 11
Burden of proof
1. Any lack of conformity which becomes apparent within one year of the time when the goods were delivered shall be presumed to have existed at the time when the goods were delivered, unless proved otherwise or unless this presumption is incompatible with the nature of the goods or with the nature of the lack of conformity. This paragraph shall also apply to goods with digital elements.
2. Instead of the one-year period laid down in paragraph 1, Member States may maintain or introduce a period of two years from the time when the goods were delivered.
I believe it's this one:
https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CEL...
codified in Germany as ยง477 BGB (other countries accordingly)
edit: Article 11
Burden of proof
1. Any lack of conformity which becomes apparent within one year of the time when the goods were delivered shall be presumed to have existed at the time when the goods were delivered, unless proved otherwise or unless this presumption is incompatible with the nature of the goods or with the nature of the lack of conformity. This paragraph shall also apply to goods with digital elements.
2. Instead of the one-year period laid down in paragraph 1, Member States may maintain or introduce a period of two years from the time when the goods were delivered.