diff --git a/custom_components/pronote/const.py b/custom_components/pronote/const.py
index ae42e58..2776a50 100644
--- a/custom_components/pronote/const.py
+++ b/custom_components/pronote/const.py
@@ -20,5 +20,6 @@
 DEFAULT_REFRESH_INTERVAL = 15
 DEFAULT_ALARM_OFFSET = 60
 DEFAULT_LUNCH_BREAK_TIME = "13:00"
+TIMETABLE_PERIOD_MAX_LESSONS = 16
 
 PLATFORMS = [Platform.SENSOR, Platform.CALENDAR]
diff --git a/custom_components/pronote/coordinator.py b/custom_components/pronote/coordinator.py
index f963e7c..15fd321 100644
--- a/custom_components/pronote/coordinator.py
+++ b/custom_components/pronote/coordinator.py
@@ -93,8 +93,27 @@ def get_evaluations(period):
 
 
 def get_overall_average(period):
+    """Return overall average as a real number.
+
+    Some Pronote backends expose the overall average using a localized string
+    (e.g. "13,2"). Home Assistant numeric_state conditions require a value
+    that can be parsed as a float, so we normalise the decimal separator here.
+    """
     try:
-        return period.overall_average
+        overall = period.overall_average
+        if overall is None:
+            return None
+
+        # If Pronote returns a localized string like "13,2", normalise it.
+        if isinstance(overall, str):
+            normalized = overall.replace(",", ".")
+            try:
+                return float(normalized)
+            except (TypeError, ValueError):
+                # If parsing fails, fall back to the raw value.
+                return overall
+
+        return overall
     except Exception as ex:
         _LOGGER.info(
             "Error getting overall average from period (%s): %s", period.name, ex
diff --git a/custom_components/pronote/pronote_formatter.py b/custom_components/pronote/pronote_formatter.py
index fc48322..1b1a91a 100644
--- a/custom_components/pronote/pronote_formatter.py
+++ b/custom_components/pronote/pronote_formatter.py
@@ -46,6 +46,23 @@ def format_lesson(lesson, lunch_break_time):
         "is_afternoon": lesson.start.time() >= lunch_break_time,
     }
 
+def format_compact_lesson(lesson, lunch_break_time):
+    """Compact representation of a lesson for long-range timetable sensors.
+
+    Only keep timing and label fields to reduce attribute size.
+    """
+    return {
+        "start_at": lesson.start,
+        "end_at": lesson.end,
+        "start_time": lesson.start.strftime("%H:%M"),
+        "end_time": lesson.end.strftime("%H:%M"),
+        "lesson": format_displayed_lesson(lesson),
+        "classroom": lesson.classroom,
+        "canceled": lesson.canceled,
+        "status": lesson.status,
+        "is_morning": lesson.start.time() < lunch_break_time,
+        "is_afternoon": lesson.start.time() >= lunch_break_time,
+    }
 
 def format_attachment_list(attachments):
     return [
diff --git a/custom_components/pronote/sensor.py b/custom_components/pronote/sensor.py
index 6ff04c4..5212900 100644
--- a/custom_components/pronote/sensor.py
+++ b/custom_components/pronote/sensor.py
@@ -21,6 +21,7 @@
     GRADES_TO_DISPLAY,
     EVALUATIONS_TO_DISPLAY,
     DEFAULT_LUNCH_BREAK_TIME,
+    TIMETABLE_PERIOD_MAX_LESSONS,
 )
 
 
@@ -290,7 +291,13 @@ def __init__(
 
     @property
     def extra_state_attributes(self):
-        """Return the state attributes."""
+        """Return the state attributes.
+
+        For daily timetable sensors (today, tomorrow, next day), we expose all lessons.
+        For the period timetable sensor (``lessons_period``), we only expose upcoming
+        lessons (starting from "now") and cap the number of lessons to avoid exceeding
+        Home Assistant recorder attribute size limits.
+        """
         lessons = self.coordinator.data[self._key]
         attributes = []
         canceled_counter = None
@@ -299,6 +306,7 @@ def extra_state_attributes(self):
             "lessons_tomorrow",
             "lessons_next_day",
         ]
+        is_period = self._key == "lessons_period"
         lunch_break_time = datetime.strptime(
             self.coordinator.config_entry.options.get(
                 "lunch_break_time", DEFAULT_LUNCH_BREAK_TIME
@@ -312,11 +320,29 @@ def extra_state_attributes(self):
             self._lunch_break_start_at = None
             self._lunch_break_end_at = None
             canceled_counter = 0
-            for lesson in lessons:
-                index = lessons.index(lesson)
-                if not (
-                        lesson.start == lessons[index - 1].start and lesson.canceled is True
-                ):
+
+            # For the period timetable, keep only upcoming lessons and limit the count.
+            if is_period:
+                now = datetime.now()
+                filtered_lessons = [
+                    lesson for lesson in lessons if lesson.start >= now
+                ]
+                if len(filtered_lessons) > TIMETABLE_PERIOD_MAX_LESSONS:
+                    filtered_lessons = filtered_lessons[:TIMETABLE_PERIOD_MAX_LESSONS]
+            else:
+                filtered_lessons = lessons
+
+            for index, lesson in enumerate(filtered_lessons):
+                # Skip duplicated canceled lessons that share the same start time
+                # as the previous one.
+                if index > 0:
+                    previous = filtered_lessons[index - 1]
+                    if lesson.start == previous.start and lesson.canceled is True:
+                        continue
+
+                if is_period:
+                    attributes.append(format_compact_lesson(lesson, lunch_break_time))
+                else:
                     attributes.append(format_lesson(lesson, lunch_break_time))
                 if lesson.canceled is False and self._start_at is None:
                     self._start_at = lesson.start
@@ -327,8 +353,8 @@ def extra_state_attributes(self):
                     if lesson.end.time() < lunch_break_time:
                         self._lunch_break_start_at = lesson.end
                     if (
-                            self._lunch_break_end_at is None
-                            and lesson.start.time() >= lunch_break_time
+                        self._lunch_break_end_at is None
+                        and lesson.start.time() >= lunch_break_time
                     ):
                         self._lunch_break_end_at = lesson.start
 
@@ -666,4 +692,4 @@ def extra_state_attributes(self):
 
         attributes["periods"] = periods
 
-        return attributes
+        return attributes
\ No newline at end of file