Apparently it is France that has taken upon itself the task of making clandestine naval war upon Russia. France seems to be the party that has sunk several Russian oil tankers recently, and as of now Russia hasn't attacked French ships or ports in return.
French President Macron has a smaller naval force than Russia yet it is technically modern and sophisticated, including the only European aircraft carrier. It is tempting for rulers of countries with a large, sophisticated military with a technical advantage over an enemy not to use their resources to attack.
Russia of course has several options for counterattacking should it choose to. France obviously is hiding behind the N.A.T.O. shield to engage in war at its pleasure- striking out at a powerful adversary like a cobra- an adversary that doesn't wish to expand the war to include France and potentially N.A.T.O.
The French President Macron seeks to stop Russian oil sales to China and elsewhere that is an important source of cash to fund its war stressed economy. Russia probably will do some kind of cost-benefit analysis to determine if it is a good idea to take out Marseilles and Le Havre's port infrastructures with something like submarine drones or air launched torpedoes with APR-3Es or Murena-300S etc.
The United States will certainly be tested by the new European confidence that it can attack Russian interests with impunity; America cannot be the blaster in a master-blaster Thunderdome relationship without forfeiting moral and political leadership in the relationship of N.A.T.O. treaty obligations. The idea that European nations can attack whoever they want and the United States will defend them if the countries counterattack the European aggressor is not a policy that is desirable or sustainable from an American perspective.
President Macron visited China to speak with Xi Jinping and boast how the Russians will suffer significant financial damage in the near future (from the loss of oil sales revenue). The French having rejoined the N.A.T.O. military command long after the Cold War concluded (in 2009 during the Obama administration) see only advantages in levering the anachronistic treaty that is dangerous for U.S. strategic interests now and down the road. A new international security arrangement will need to be found. The N.A.F.T.A. treaty was renegotiated by President Trump; perhaps a new N.A.T.O. treaty should be found that limits the numbers of members and requires some sort of a rational use of the joint military power such that individual members that first attack another nation, cannot use the treaty for mutual defense to expect mutual defense when they are the aggressor first striking a foreign power, as the French have on Russia.