The Relevant Act does not provide provisions on international private law, so the general rules of international private law apply.
If the consumer loan agreement is lawfully governed by foreign law, such a choice of foreign law may not, however, have the result of depriving the consumer of the protection afforded to him by mandatory consumer protecting provisions of the country where the consumer has his habitual residence (Art. 6 para. 2 Rome I Regulation). The exclusion of the lender's right to terminate the consumer loan due to a significant deterioration of the financial circumstances of the consumer or the value of a security (see below section “Impact on the loan agreements”) is such a mandatory provision and therefore also applies to loans to German consumers lawfully governed by foreign law.
On the other hand, the statutory payment moratorium is non-mandatory as the borrower may continue its payments and the parties may agree otherwise (see above section “Description of the legislation”). So Art. 6 para. 2 Rome I Regulation does most likely not apply. On the other hand, although this is not clear yet, the Relevant Act in its entirety could be considered an overriding mandatory provision (Eingriffsnorm) in the meaning of Art. 9 Rome I Regulation as it pursuits public interests. If this is true, a foreign court may (not: must) apply the provisions of the German statutory payment moratorium also to a loan agreement with a German consumer that is lawfully governed by such foreign law (Art. 9 para. 3 Rome I Regulation).
Of course, if in each case the chosen law is more favourable to the consumer, the consumer may also choose to exercise the rights afforded to him or her under the chosen law.