Appliquer un gabarit aux pages imparies d'un document indesign

Ton document n'est pas monté en recto-verso ?

This is a feature that really should be part of the program. You can log it as a feature request at https://indesign.uservoice.com/forums/601021-adobe-indesign-feature-requests. 

Ah I think you want to apply a Parent Page to all odd pages or even pages

This script will do the trick

// Apply selected Parent (Master) to Odd, Even, or All pages
// Works in InDesign CC and later
// by Eugene Tyson

if (app.documents.length === 0) {
    alert("Please open a document first.");
} else {
    var doc = app.activeDocument;
    var masters = doc.masterSpreads;

    if (masters.length === 0) {
        alert("This document has no parent/master pages.");
    } else {
        // Build list of master names
        var masterNames = [];
        for (var i = 0; i < masters.length; i++) {
            masterNames.push(masters[i].name);
        }

        // --- Build dialog ---
        var w = new Window("dialog", "Apply Parent to Pages");
        w.orientation = "column";
        w.alignChildren = ["fill", "top"];
        w.spacing = 10;
        w.margins = 16;

        w.add("statictext", undefined, "Select a Parent/Master Page:");
        var dropdown = w.add("dropdownlist", undefined, masterNames);
        dropdown.selection = 0;

        w.add("statictext", undefined, "Apply to:");
        var applyGroup = w.add("group");
        applyGroup.orientation = "row";
        var optOdd = applyGroup.add("radiobutton", undefined, "Odd pages");
        var optEven = applyGroup.add("radiobutton", undefined, "Even pages");
        var optAll = applyGroup.add("radiobutton", undefined, "All pages");
        optOdd.value = true; // default

        // Buttons
        var btnGroup = w.add("group");
        btnGroup.alignment = "right";
        var okBtn = btnGroup.add("button", undefined, "Apply", {name: "ok"});
        var cancelBtn = btnGroup.add("button", undefined, "Cancel", {name: "cancel"});

        // --- Apply logic ---
        if (w.show() === 1) {
            var selectedMasterName = dropdown.selection.text;
            var selectedMaster = doc.masterSpreads.itemByName(selectedMasterName);
            var pages = doc.pages;
            var appliedCount = 0;

            app.doScript(function() {
                for (var i = 0; i < pages.length; i++) {
                    var page = pages[i];
                    var pageNum = parseInt(page.name, 10);

                    var applyThis =
                        (optAll.value) ||
                        (optOdd.value && pageNum % 2 !== 0) ||
                        (optEven.value && pageNum % 2 === 0);

                    if (applyThis) {
                        page.appliedMaster = selectedMaster;
                        appliedCount++;
                    }
                }
            }, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, "Apply Parent to Pages");

            alert("Applied '" + selectedMasterName + "' to " + appliedCount + " pages.");
        }
    }
}