(n.) an unscrupulous or exploitative hack journalist
A boulevard-journalist is an unscrupulous journalist or hack writer.
That definition was taken from JR Ware’s Passing English of the Victorian Era, a retrospective dictionary of nineteenth century slang and colloquial English published in 1909. As Ware explains, the term dates from the early 1850s, when the French President Louis-Napoleon Bonaparte—barred by both the French constitution and his own parliament from serving a second term—overruled all opposition and essentially staged a coup d’état to give himself almost unassailable power across the country.
Supported by two sweeping referenda (the free nature and outcome of which were both called into question by many of his opponents), in 1852 the president took it upon himself to dissolve the French National Assembly, reestablish the French Empire, and—on the anniversary of his uncle Napoleon Bonaparte’s coronation—crown himself Emperor Napoleon III of France.
Understandably, not everyone was happy.
But with the politicians of the day now effectively powerless, it fell to the press to oppose the emperor’s new regime. Disgruntled writers and journalists all across Paris were soon publishing and distributing vitriolic journals and pamphlets full of scandalous rumours, personal slights and vocal remonstrations against the newly-crowned Emperor. The legitimate press labelled these crude newspapers les journaux des boulevards, or ‘street journals’, while those who wrote for them were les journalistes boulevardiers—or ‘boulevard journalists’.
The term was quickly borrowed into English after these journals and journalists turned their anger against the British in 1853, when Great Britain and the reformed French Empire entered into an alliance against Russia in the Crimean War.
Although the Crimean campaign proved successful, the subsequent Franco-Prussian War was not, and Napoleon was captured at the Battle of Sedan in 1870. In his absence, the Empire collapsed and a new French Republic was declared on 4 September. He never again took power, and died in exile in England in 1873.