Not to be picky, but you can love only another human being or God; you can enjoy football (soccer) or you can like Fido, but not love them.
You can check http://www.howmanyofme.com/search/.
Common or uncommon, you must consider life:
People adopt children; the adoptees usually go by the adopters surname.
Women marry; in most countries, the wives go by the husband's surname. If they are divorced, the wife can keep her married name; she can then become pregnant by another man and their child can go by the surname of her previous husband.
People are constantly changing their names; you will notice that it is one of the most frequently asked questions on this site.
Algeria, being part of the Magreb, has a heavy influence from Europeans.
France and Germany have been at war with each other (other the European tribe who inhabited those present-day countries) for thousands of years. Many Frenchmen have German surnames and vice versa.
But, yes, generally speaking they claim that people with the same surname are more likely related if it is a rare surname.
But, as in all questions pertaining unto genealogy, the only way to find out is to do the research. Failing that, you can try to find out if your surname originated in only one place, or thousands of places as in the case of Smith, and then attempt to find out the history of that location.