French atrocities against civilians in the Peninsular War
A difficult topic, but one that is often 'dismissed' by Francophile historians as too common, was the French Army's behaviour towards the civilian population when it invaded a country. Here the focus is on Spain & Portugal, though there were cases in many other invasions, Napoleon had already encouraged his troops to loot and kill after seiges in Italy and after the seige of Jaffar he ordered thousands of captive civilians killed at bayonet point (in order to save ammunition) For examples in Russia see: https://www.lrb.co.uk/the-paper/v31/n23/geoffrey-hosking/peasants-in-arms)
This is not to say that the British Army behaved angelically, though allied and invited to liberate Portugal & Spain from Napoleon's aggressive expansionism. The retreat to Corunna in 1809 ‘remains a dark chapter in the history of the British army’ (Charles Esdaile), and the sacking of Ciudad Rodrigo, Badajoz and San Sebastian were abysmal incidents, which caused Wellington to fly into a rage and order the hanging of perpetrators on the spot. The differential factor is that the French were ordered to use the murder (and worse) and fear as a weapon as well as individual crimes and on the whole the British Army at least tried to convict those caught and Wellington was clear on harsh punishments for any crimes committed on their allies.
In the Autumn of 1807 Napoleon ordered General Jean-Andoche Junot along with over 24,000 men to invade the neutral nation of Portugal, to end it's trade with Britain, which it refused to cease (the was a alliance with Britain which dated back to the the 14th Century). No military resistance was offered (The only resistance was offered by the governor of Valenca, who refused to open his gates to the northern column. He only caved in when he found that Lisbon had fallen and the Royal family had already fled to Brazil)
Junot was instructed to seize the property of the 15,000 persons who had fled to Brazil and to levy a 100 million Franc fine on the nation. As it happened, the refugees had carried off almost half of the specie in Portugal and the French were barely able to raise enough money to maintain the occupation army. Nevertheless, the harsh taxes caused bitter resentment among the population. By January 1808 there were open executions of civilians who resisted the heavy handed demands of the French. Meanwhile in Spain, King Charles IV, France's supposed ally, was forced to abdicate in favour of his son, all of whom were held captive in Bayonne. The remaining children of the royal family were then forcibly ordered to join their parents in France. This led to a spontaneous uprising in Madrid; The Dos de Mayo. What followed was street fighting in different areas of Madrid as the poorly armed population confronted the occupying French troops. There were only a few Spanish military leaders involved, most of whom had been planning a campaign away from the capital and were caught unawares. The uprising was brutally put down by French Troops, street by street, famously having to storm a Spanish artillery barracks which was bravely defended.
[El dos de Mayo / The Charge of the Mamelukes. By Goya - The Prado]
The repression following the crushing of the initial rebellion was harsh. A special military commission was created on the evening of 2 May to be presided over by General Grouchy. This commission issued death sentences to all of those captured who were bearing weapons of any kind. In a statement issued that day Murat said: "The population of Madrid, led astray, has given itself to revolt and murder. French blood has flowed. It demands vengeance. All those arrested in the uprising, arms in hand, will be shot."
These initial executions against cooperation, as in Portugal or reprisal killings, as in Spain formed a pattern for the French behaviour during the Peninsular War that followed.
[Tres De Mayo by Goya - The Prado]
As the Spanish uprisings became open revolt against their invaders and evolved into successful Guerrilla War elements to liberate their nation, the French Army used murder and fear as a weapon, under orders and spontaneously alike.
There is far less detail given in French memoirs, given on how they carried out orders to sack villages and spare no one (sometimes enthusiastically as the loot provided a chance for the soldiers to gain great valuables). Joseph de Naylies, a French officer (who later because a Captain in the Eclaireurs of the Imperial Guard) wrote, "we entered the town... which was immediately pillaged and reduced to ash... We burnt [it down] and killed everyone we found there"
Maurice de Tascher, another French officer, but who was related to the Empress Josephine wrote a more harrowing account of the sacking of Cordoba; 30th June 1808:
"The Cathedral and the sacred lives within were not spared, which made the Spanish look upon us in horror, saying out loud that they would prefer we violated their women than their churches. We did both. The convents had to suffer all that debauchery has invented and the outrages of the soldier given up to himself"
Chart: Murders in the 2nd French Invasion of Portugal (1810-1811) in 1 district. Source University of Coimbra.
The Duke of Wellington wrote of the murder, thefts and worse: "The British people, I'm certain, wouldn't believe the indecent behaviours of the French after their retreat. I have never seen, nor heard, nor read of such behaviour and am convinced their actions have no equal in world history. You will hear several shocking recounts which should be told to the world at large.
They killed all the countryfolk they found. Every day, we found the bodies of women, young and old, who were either stabbed, or shot. Since we were near Condexia, they regularly sent patrols to fetch all girls over the age of 10 to the camp to satisfy the soldiery... Every child we met was in tears, mourning the death of a parent. The houses were systematically burned ... They dug up and looted the graves.
Two days ago, one of our patrols entered a village where they found 36 corpses, most of whom were in their beds..." It's worth noting the the British public and Parliament were already well motivated against Napoleon as a threat towards Britain. The fear of invasion was tangible, especially in London and along the South coast. Wellington was not prone to exaggeration, nor did he often write graphic descriptions of the war he witnessed (for example the aftermath of Waterloo so deeply upset him, that he refused to talk about it), so we can presume his writing is factual.
Writing for Land of History: https://adventuresinhistoryland.com a collection of excellent articles and blogs by Josh Provan, which I can strongly recommend.
Charles Oman: History of the Peninsular War