A court in Algeria on Tuesday upheld Franco-Algerian author Boualem Sansal's five-year prison sentence in a case that has raised alarm over freedom of expression in Algeria and pushed tensions with France to the brink.

An Algerian court upheld on Tuesday a five-year prison sentence being served by French-Algerian writer Boualem Sansal for undermining national unity, Ennahar TV said, prompting a call for clemency by France.

The conviction of Boualem Sansal, an outspoken French and Algerian writer, has worsened tensions between the countries.