Deuteronomy 15:3

From a son of the Gentiles thou mayest exact, but the lawful right (dina) which is thine with thy brother thou shalt release with thine hand.

You may press the foreigner for payment i.e., it is permissible.

OF AN ALIEN ‘TIGOS’ (THOU MAYEST EXACT IT). “This constitutes a positive commandment.” Thus is Rashi’s language quoting the Sifre. 113. The meaning thereof is that there is a positive commandment with respect to your brother [that you are not to exact the debt from him after it was cancelled by the Sabbatical year, the reasoning being as follows]: of an ‘alien’ thou mayest exact it, but not from your brother, and a negative commandment derived from a positive commandment carries the force of a positive commandment.]. Now, by Scripture stating of an alien thou shalt exact it, we infer that one may not exact it from an Israelite, and since a negative commandment that is derived by implication from a positive commandment has the force of the positive injunction from which it is derived — it follows that he, who exacts it from an Israelite, violates both an explicit negative commandment and an implied positive commandment. This is the intent of the Sifre, but not as stated by Rashi that there is a positive commandment to exact it from the heathen. See “The Commandments,” Vol. I, pp. 150-151, where Rashi’s position coincides with that of Rambam, and Ramban differs with him. And because we have been taught there [in the Sifre]: “He shall not exact it [of his neighbor and his brother] — it is a negative commandment upon him,” therefore the Rabbis again taught: “Of an alien thou shalt exact it — this is a positive commandment,” [not to exact the debt from a brother] meaning to say that he who exacts the debt from his brother violates both a positive commandment and a negative commandment.
In the same way the Rabbis have said there: 263. “Unto an alien ‘thashich’ (mayest thou lend upon interest) — it is a positive commandment. But unto thy brother thou shalt not lend upon interest — this is a negative commandment.” This, too, is as we have explained [that the meaning of the Sifre is] that there is a positive commandment with respect to your brother not to lend him on interest, and so did Rashi explain there, but not that there is any commandment to lend an alien on interest. It is so indicated from the Gemara of the Chapter “What is usury?”
Now Harav Rabbi Moshe ben Maimon made both of them actual commandments — to exact debts from an alien and to lend him upon interest., Positive Commandment 198. He erred regarding these texts taught in the Sifre. Such expressions are common there [in the Sifre] in many places, as for example; 103. “Of all clean fowls ye may eat — it is a positive commandment. And all winged swarming things are unclean; they shall not be eaten, Verse 19. — this is a negative commandment.”, implies that you may not eat unclean fowl. Similarly the Rabbis mentioned in the Sifra 3:2. and in the Sifre: 101. “These are the beasts which ye may eat — it is a positive commandment.” But the matter is clear [as I have explained it].