The guillotine was a device used in executions. It was frequently used by revolutionaries in 18th century France to dispose of their enemies.
In 1789, a young French aristocrat named Jason (a.k.a. Marquis de Saint Epiman de Sinee de la Tour) was sentenced to death by guillotine but was rescued by the Sixth Doctor and became his companion. Later, the meddling of a Dalek caused the TARDIS to return to revolutionary France. Jason was arrested once more and his sentence was almost carried out but he managed to escape again. (AUDIO: The Ultimate Adventure)
In July 1794, Barbara Wright and Susan Foreman were scheduled to be taken to the guillotine, but they were rescued by Jules Renan and Jean. (TV: The Reign of Terror)
When the Cardiff Space-Time Rift fractured in 2008, mixing space and time periods, a guillotine appeared in Paris. (TV: End of Days)