diff --git a/r2-shared/build.gradle b/r2-shared/build.gradle
index 204b1114..78849088 100644
--- a/r2-shared/build.gradle
+++ b/r2-shared/build.gradle
@@ -53,6 +53,7 @@ dependencies {
 
     testImplementation "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version"
     testImplementation 'junit:junit:4.12'
+    testImplementation 'org.assertj:assertj-core:3.14.0'
     testImplementation 'org.mockito:mockito-core:2.19.0'
     testImplementation 'xmlpull:xmlpull:1.1.3.1'
     testImplementation 'net.sf.kxml:kxml2:2.3.0'
diff --git a/r2-shared/src/main/java/org/readium/r2/shared/URLHelper.kt b/r2-shared/src/main/java/org/readium/r2/shared/URLHelper.kt
index a3153b5b..1aac1542 100644
--- a/r2-shared/src/main/java/org/readium/r2/shared/URLHelper.kt
+++ b/r2-shared/src/main/java/org/readium/r2/shared/URLHelper.kt
@@ -11,13 +11,14 @@ package org.readium.r2.shared
 
 import android.net.Uri
 import java.net.URI
+import java.net.URLDecoder
 
 fun getAbsolute(href: String, base: String): String {
     return try {
         val baseURI = URI.create(base)
         val relative = baseURI.resolve(href)
         relative.toString()
-    }catch (e:IllegalArgumentException){
+    } catch (e:IllegalArgumentException){
         val hrefUri = Uri.parse(href)
         if (hrefUri.isAbsolute){
             href
@@ -27,26 +28,24 @@ fun getAbsolute(href: String, base: String): String {
     }
 }
 
-
-internal fun normalize(base: String, in_href: String?) : String {
-    if (in_href == null || in_href.isEmpty()) {
-        return ""
-    }
-    val hrefComponents = in_href.split( "/").filter { it.isNotEmpty() }
-    val baseComponents = base.split( "/").filter { it.isNotEmpty() }
-    baseComponents.dropLast(1)
-
-    val replacementsNumber = hrefComponents.filter { it == ".." }.count()
-    var normalizedComponents = hrefComponents.filter { it != ".." }
-    for (e in 0 until replacementsNumber) {
-        baseComponents.dropLast(1)
-    }
-    normalizedComponents = baseComponents + normalizedComponents
-    var normalizedString = ""
-    for (component in normalizedComponents) {
-        normalizedString += "/$component"
+fun normalize(base: String, href: String?): String {
+    val resolved = if (href.isNullOrEmpty()) ""
+    else try { // href is returned by resolve if it is absolute
+        val absoluteUri = URI.create(base).resolve(href)
+        val absoluteString = absoluteUri.toString() // this is a percent-decoded
+        val addSlash = absoluteUri.scheme == null && !absoluteString.startsWith("/")
+        (if (addSlash) "/" else "") + absoluteString
+    } catch (e: IllegalArgumentException){ // one of the URIs is ill-formed
+        val hrefUri = Uri.parse(href) // Android Uri is more forgiving
+        // Let's try to return something
+        if (hrefUri.isAbsolute) {
+            href
+        } else if (base.startsWith("/")) {
+            base + href
+        } else
+            "/" + base + href
     }
-    return normalizedString
+    return URLDecoder.decode(resolved, "UTF-8")
 }
 
 
diff --git a/r2-shared/src/test/java/org/readium/r2/shared/URLHelperTest.kt b/r2-shared/src/test/java/org/readium/r2/shared/URLHelperTest.kt
new file mode 100644
index 00000000..e3b31ad0
--- /dev/null
+++ b/r2-shared/src/test/java/org/readium/r2/shared/URLHelperTest.kt
@@ -0,0 +1,44 @@
+/*
+ * Module: r2-streamer-kotlin
+ * Developers: Quentin Gliosca
+ *
+ * Copyright (c) 2018. Readium Foundation. All rights reserved.
+ * Use of this source code is governed by a BSD-style license which is detailed in the
+ * LICENSE file present in the project repository where this source code is maintained.
+ */
+
+package org.readium.r2.shared
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.Test
+
+class NormalizeTest {
+    @Test
+    fun `Anchors are accepted as href`() {
+        assertThat(normalize("OEBPS/xhtml/nav.xhtml", "#toc")).isEqualTo("/OEBPS/xhtml/nav.xhtml#toc")
+    }
+
+    @Test
+    fun `Directories are accepted as base`() {
+        assertThat(normalize("OEBPS/xhtml/", "nav.xhtml")).isEqualTo("/OEBPS/xhtml/nav.xhtml")
+    }
+
+    @Test
+    fun `href is returned unchanged if it is an absolute path`() {
+        assertThat(normalize("OEBPS/content.opf", "/OEBPS/xhtml/index.xhtml")).isEqualTo("/OEBPS/xhtml/index.xhtml")
+    }
+
+    @Test
+    fun `href is returned unchanged if it is an absolute URI`() {
+        assertThat(normalize("OEBPS/content.opf", "http://example.org/index.xhtml"))
+    }
+
+    @Test
+    fun `Result is percent-decoded`() {
+        val base = "OEBPS/xhtml/%E4%B8%8A%E6%B5%B7%2B%E4%B8%AD%E5%9C%8B/base.xhtml"
+        val href = "%E4%B8%8A%E6%B5%B7%2B%E4%B8%AD%E5%9C%8B.xhtml"
+        assertThat(normalize(base, href)).isEqualTo("/OEBPS/xhtml/上海+中國/上海+中國.xhtml")
+        assertThat(normalize("OEBPS/xhtml%20files/nav.xhtml", "chapter1.xhtml")).isEqualTo("/OEBPS/xhtml files/chapter1.xhtml")
+
+    }
+}
\ No newline at end of file