On 14 January 1858, an Italian refugee from Britain called Orsini attempted to assassinate Napoleon III with a bomb made in England. The ensuing diplomatic crisis destabilised the government, and Palmerston resigned. Derby was reinstated as prime minister. Victoria and Albert attended the opening of a new basin at the French military port of Cherbourg on 5 August 1858, in an attempt by Napoleon III to reassure Britain that his military preparations were directed elsewhere. On her return Victoria wrote to Derby reprimanding him for the poor state of the Royal Navy in comparison to the French one. Derby's ministry did not last long, and in June 1859 Victoria recalled Palmerston to office.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): What new military port in France did Victoria and Albert visit after the crisis in 1858?
Cherbourg