Interestingly, though, there were but seven prisoners in the Bastille at the time it was liberated: four forgers, two “lunatics” and one “deviant” aristocrat, the comte de Solages. The Marquis de Sade had been transferred out 10 days earlier, according to Wikipedia.
The Bastille, in general, largely held common criminals, as well as people imprisoned for religious reasons and those responsible for printing or writing forbidden pamphlets. People of high rank were sometimes held there too, and so the building (which could only hold a little over 50 people) was far less sordid a place than most Parisian prisons.
But the secrecy maintained around the Bastille and its prisoners gave it a sinister reputation, according to Wikipedia.
However, the cost of maintaining a medieval fortress, built in the 14th Century, and garrison for so limited a purpose had led to a decision being taken to close it, shortly before the disturbances began.
By July 1789, the Bastille was manned by fewer than 100 invalides, or veteran soldiers no longer fit for service in the field. They were reinforced by fewer than three dozen Swiss soldiers. In addition to the handful of prisoners, they watched over gunpowder and and arms.
Tensions had been on the rise in Paris for sometime prior to the fateful day. In the early afternoon of July 14, after fruitless negotiations between French citizens and the buildings garrison, between 600-1,000 French citizens attacked the stronghold, seeking gunpowder and arms.
After several hours, the fortress was taken. Approximately 100 of the attackers were killed along with one of the defenders, though several of the latter were later killed by the crowd.
The storming of The Bastille sparked insurrection and a spirit of popular sovereignty throughout France, and was a key factor in the downfall of the Capetian Monarchy and onset of the French Revolution.