The announcement came as UK Prime Minister Theresa May and French President Emmanuel Macron held a bilateral summit meant to strengthen their security and intelligence ties as Britain negotiates its exit from the European Union.
Hundreds of people continue to camp out in the northern French town, hoping to stow away on trucks heading to Britain, a destination seen as an El Dorado by some migrants from Afghanistan and parts of Africa.
France would "look with kindness" on a decision by Britain to reverse the course of Brexit and remain in the European Union, an adviser to President Emmanuel Macron said on Wednesday.
With Brexit looming overhead, U.K. Prime Minister Theresa May and French President Emmanuel Macron are working to preserve ties between their two countries.
"If you want access to the single market - including the financial services - be my guest".
Asked why he wanted to exclude financial services from a future UK-EU free trade agreement, Mr Macron said: "I am here neither to punish nor to reward".
The two leaders stressed the close security partnership between France and Britain, which they agreed should not be affected by Britain's departure from the EU.
France's PSA Group to offer 40 electric models by 2025
Peugeot already is beginning to offer ride services in the United States through its Free2Move brand, using other companies' cars. Tavares and a company spokesman clarified that electrification will be an option on all the automaker's vehicles by that time.
In a boost to Macron, Britain is also throwing its backing behind the European Intervention Initiative, a multinational European military force that the French president has proposed.
The heads of MI5, MI6, GCHQ and France's DGSE and DGSI will meet to discuss how the United Kingdom and its allies across the Channel can work to counter threats such as the targeting of concert venues like Manchester Arena and the Bataclan in Paris, and terrorists using the internet as a "safe space".
Child migrants seeking to escape Calais and come to Britain will have their claims processed within 25 days, after French President Emmanuel Macron persuaded Theresa May to adopt what he called a "humane approach".
May and Macron are said to have a good personal relationship and are at ease in each other's company and earlier in the day she invited him for a pub lunch in her constituency.
Mr Macron said the Sandhurst Treaty signed on Thursday - the first joint treaty on the Calais border in 15 years - would "enable us to improve the relationship and the management of the joint border" and reduce the time taken to process migrants. The announcement followed France playing its own diplomatic card with a promise to loan Britain the Bayeux Tapestry.
France in turn has agreed to commit troops to the British-led North Atlantic Treaty Organisation battlegroup in Estonia in 2019. A French human rights commission in 2015 said the accord had made France the "police branch" of Britain's immigration policies.
The summit, created to underline that the relationship between the two nations goes beyond Brexit, included ministers for foreign affairs, defense, security and culture. When it comes to Europe, these two countries are pulling in radically different directions.