Luis Medina-Zavala (Medina) appeals his conviction and the 57-month sentence he received after he pleaded guilty to illegal reentry. Medina argues that his sentence is illegal under United States v. Booker, 543 U.S. 220, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005), because it was imposed pursuant to a mandatory application of the federal Sentencing Guidelines.

The erroneous application of the Guidelines as mandatory is technically a “Fanfan error.” United States v. Martinez-Lugo, 411 F.3d 597, 600 (5th Cir.), cert. denied, — U.S. -, 126 S.Ct. 464, 163 L.Ed.2d 352 (2005); see Booker, 125 S.Ct. at 750, 768-69. The Government concedes that Medina preserved his Fanfan claim for appeal and that the issue is reviewed for harmless error. See United States v. Walters, 418 F.3d 461, 464 (5th Cir. 2005). The Government also concedes that, given the district court’s acknowledgment that Medina raised good points challenging his criminal history computation and the court’s statement that it “got no satisfaction” in sentencing Medina, the district *606 court’s error in sentencing Medina under mandatory Guidelines was not harmless. Because the Government fails to meet its burden of showing that the district court’s error was harmless beyond a reasonable doubt, we vacate the sentence and remand the case for resentencing in accordance with Booker.

Medina also argues 8 U.S.C. § 1326 is unconstitutional. As he concedes, this argument is foreclosed by Almendarez-Torres v. United States, 523 U.S. 224, 118 S.Ct. 1219, 140 L.Ed.2d 350 (1998), which this court must follow “unless and until the Supreme Court itself determines to overrule it.” United States v. Izaguirre-Flores, 405 F.3d 270, 277-78 (5th Cir.) (quotation marks omitted), cert. denied, - U.S. -, 126 S.Ct. 253, 163 L.Ed.2d 231 (2005). The judgment of conviction is affirmed.

CONVICTION AFFIRMED; SENTENCE VACATED; CASE REMANDED.