Certainly Dickens captured the gritty reality of the French Revolution. The descriptions Dickens uses paints a vivid picture of the dire predicaments of the poor. People were desperate for food and clean water. The same fountains where they drew their drinking and cooking water were the same fountains used for washing. Desperation led to mobs that stormed the Bastille and wreaked havoc on Paris. The guillotine was a fact of life toward the end of the Revolution, ending the lives of both guilty and innocent.
The Romanticism in the book comes in the plot and characters. The probabilities that one man would give his life for another for the love of a woman are pretty low. The noble ideals of Darnay and Dr Manett are truly Romantic ideals.
Dickens uses the Romantic language and plot elements to drive his report on the horrors of revolution so that England could avoid a similar tragedy.