Another answer says, without qualification (emphasis mine): "Lying per se is not illegal. For it to be so, the person lied to has to suffer a detriment that the lier [sic] ought to prevent."
But, are there lies that are considered illegal without any demonstrated detriment?
Yes.
For just one of many examples, see s. 52 of Canada's Competition Act, which makes it an offence to display a false or misleading advertisement. Section 52 expressly says that "it is not necessary to prove that ... any person was deceived or misled." In this context, it is the falsehood that is punished, for its own sake.
* This answer is not really about the full scope of s. 52, but to address a comment wondering about parody, subsection (4) avoids parody being caught by the prohibition: "the general impression conveyed by a representation as well as its literal meaning shall be taken into account in determining whether or not the representation is false or misleading in a material respect."
Yes.
In the wonderfully-named United States v. 11¼ Dozen Packages of Article Labeled in Part Mrs. Moffat's Shoo Fly Powders for Drunkenness, an in rem proceeding, the District Court for the Western District of New York ordered the condemnation and destruction of the packages described in the caption, because they were misbranded. They contained tartar emetic, which induces vomiting and is also poisonous at the dose recommended on the box, and is in no way a legitimate cure or treatment for drunkenness, so the court found that the label was false and misleading, and ordered the packages condemned. The court did note that expert witnesses had testified that tartar emetic was poisonous and potentially harmful, but the final judgment was solely that they were misbranded.
TL;DR: In the United States, drugs whose labels are false and misleading may be subject to condemnation and destruction. There are similar laws applicable to food (see for example United States v. 95 Barrels of Vinegar, which is perhaps an even better example because the product in that case was entirely harmless and it was purely a matter of quality).
Yes
This is not a comprehensive list, but here are some examples:
It is unlawful for a business to make statements in trade or commerce that: are misleading or deceptive; or are likely to mislead or deceive.
A lie is, by definition, misleading or deceptive but the prohibited conduct is broader than knowingly telling untruths (aka lying). Advertising puffery is excluded (e.g “Whiter than white”, “The best burgers in town”).
For a successful suit on a M&D claim, the plaintiff would need to demonstrate loss, but the conduct is also an offence. The government does not have to show that anyone was or might be harmed by the conduct; just that it happened. There is also no need to prove an intention to M&D, the conduct is sufficient.
There area number of specific lies that have been explicitly outlawed, without any need to show harm, even potential/future harm.
One prominent example is denial of the Holocaust, which is illegal in 19 countries.
"Lying per se is not illegal. For it to be so, the person lied to has to suffer a detriment that the lier [sic] ought to prevent"
That will not be correct. For example, I go to the lost and found and lie to them that I lost my iPhone, giving a precise description of the iPhone that someone else I know lost. The person lied to (the employee at the lost and found) will not suffer any detriment; the rightful owner will. Or any time to go to a shop and lie to an employee to defraud the store, the employee lied to is unlikely to suffer a detriment.
Now in court, if I lie and give a false alibi to someone who is absolutely innocent but cannot prove it, that's perjury. Even though nobody suffered (including the state who would have convicted an innocent person without my lie), it's still perjury.
